Evaluation of the microleakage of class V composite restoration after cavity treatment with Erbium, CO2 lasers, Papain, and Bromelain enzymes.

OBJECTVES: Different surface preparation and treatment methods may have dissimilar effects on the microleakage of composite resin. This study was conducted to determine the deproteinizing effect of 10% bromelain enzyme, 10% papain enzyme, CO2 , and erbium-YAG laser in regard to decrease in the microleakage of composite restorations. MATERIALS AND METHODS: Thirty teeth were selected and 60 class V cavities were prepared on the lingual and buccal sides. They were divided into six groups (n = 10): Group 1, phosphoric acid gel; Group 2, bromelain enzyme 10%; Group 3, papain enzyme 10%; Group 4, mixed papain and bromelain enzymes 10%; Group 5, CO2 laser; and Group 6, erbium-YAG laser. They were stored in basic fuchsine and dye penetration was evaluated. Kruskal-Wallis and Mann-Whitney tests were used for statistical analysis, p < 0.05 RESULTS: In both occlusal and gingival margins, comparison of microleakage between groups 1, 2, 3, 4, and 5 showed no significant differences (p = 1) and group 6 had a significant difference with other groups (p ˂ 0.001). CONCLUSIONS: Microleakage of composite resin in the dentin surface was not affected significantly using either bromelain or papain 10% enzymes or erbium laser. However, CO2 laser had a negative effect on the enamel and dentin margins and increased the microleakage. Erbium laser showed a better effect than enzymes on microleakage.

[Prospective randomized controlled trial on 2 940 nm fractional erbium laser combined with fractional micro-plasma radiofrequency in the treatment of facial atrophic acne scars].

Objective: To compare the efficacy and safety of 2 940 nm fractional erbium laser combined with fractional micro-plasma radiofrequency (FMR) therapy and 2 940 nm fractional erbium laser in the treatment of atrophic acne scars. Methods: A prospective randomized controlled research was conducted. A total of 100 atrophic acne scar patients (38 males and 62 females, aged 18-37 years) who were treated in the Scar Laser Clinic of the Department of Plastic and Reconstructive Surgery of Shanghai Ninth People's Hospital of Shanghai Jiao Tong University School of Medicine from March 2018 to March 2021 and conformed to the inclusion criteria were recruited. The patients were randomly divided into erbium laser+FMR group and erbium laser alone group, with 50 cases in each group. The facial acne scars of patients in erbium laser alone group were treated with 2 940 nm fractional erbium laser, while the facial acne scars of patients in erbium laser+FMR group were treated with erbium laser as above, besides, the scars of U and M types were treated with FMR, once every 3 months for a total of 3 times. Before the first treatment and 3 months after each treatment, the Echelle D'Assessment Clinique des Cicatrices D'Acne (ECCA) was used to score the scar. The occurrence of adverse reaction during the treatment process was observed and recorded, and the incidence was calculated. Three months after the last treatment, the 5-level classification method was used to evaluate the satisfaction of patients with the treatment effect, and the satisfaction rate was calculated. Data were statistically analyzed with independent sample t test and chi-square test. Results: A total of 89 patients completed the study, including 46 patients in erbium laser+FMR group (19 males and 27 females, aged (26±5) years) and 43 patients in erbium laser alone group (15 males and 28 females, aged (27±6) years). The ECCA scores before the first treatment and 3 months after the first treatment of patients were similar between the two groups (P>0.05). The ECCA scores of patients in erbium laser+FMR group at 3 months after the second and third treatment were 72±23 and 61±18, respectively, which were significantly lower than 85±26 and 76±25 in erbium laser alone group (with t values of -2.45 and -3.26, respectively, P<0.05). During the treatment process, the incidence of adverse reaction of patients in erbium laser+FMR group and erbium laser alone group were 23.91% (11/46) and 16.28% (7/43), respectively, and there was no statistically significant difference between the two groups (P>0.05). The satisfaction rate of patients in erbium laser+FMR group was 78.26% (36/46) at 3 months after the last treatment, which was significantly higher than 53.49% (23/43) in erbium laser alone group (χ2=6.10, P<0.05). Conclusions: The 2 940 nm fractional erbium laser combined with FMR is superior to 2 940 nm fractional erbium laser alone in the treatment of facial atrophic acne scars, achieving significantly higher efficacy without significantly increasing the incidence of adverse reaction, and patients are more satisfied with the efficacy. It can be used as a recommended therapy in clinical practice.

[Clinical observation on electroacupuncture at "four points of sacral region" on moderate to severe stress urinary incontinence after radical prostatectomy].

OBJECTIVE: To compare the clinical therapeutic effect between electroacupuncture at "four points of sacral region" and transurethral Erbium laser in treatment of moderate to severe stress urinary incontinence after radical prostatectomy. METHODS: A total of 68 patients of moderate to severe stress urinary incontinence after radical prostatectomy were divided into an electroacupuncture group (34 cases) and an Erbium laser group (34 cases, 3 cases dropped off) according to the settings. In the electroacupuncture group, electroacupuncture was applied at "four points of sacral region", i.e. points of 0.5 cun beside bilateral sacrococcygeal joints and bilateral Huiyang (BL 35), with continuous wave, 2 Hz in frequency, 60 min each time, once every other day, 3 times a week, 12 times as one course of treatment. In the Erbium laser group, transurethral Erbium laser technology was given, once every 4 weeks as one course of treatment. Both groups were treated for 5 courses. The scores of the International Consultation on Incontinence questionnaire-short form (ICI-Q-SF) and the incontinence quality of life questionnaire (I-QOL) were observed before treatment, after each course of treatment and in follow-up after 1 and 2 months of treatment completion, respectively, and the clinical efficacy was evaluated after treatment in the two groups. RESULTS: Compared with those before treatment, the ICI-Q-SF scores were decreased while the I-QOL scores were increased after 5 courses of treatment and in follow-up after 1, 2 months of treatment completion in the two groups (P<0.01). The ICI-Q-SF score in follow-up after 2 months of treatment completion were higher than that after 5 courses of treatment in the Erbium laser group (P<0.05). After 3, 4, 5 courses of treatment and in follow-up after 1 and 2 months of treatment completion, the ICI-Q-SF scores in the electroacupuncture group were lower than those in the Erbium laser group (P<0.05, P<0.01); after 2, 3, 4, 5 courses of treatment and in follow-up after 1 and 2 months of treatment completion, the I-QOL scores in the electroacupuncture group were higher than those in the Erbium laser group (P<0.01). The change ranges of ICI-Q-SF score and I-QOL score between before treatment and after each course of treatment in the electroacupuncture group were lager than those in the Erbium laser group (P<0.01, P<0.05). The total effective rate was 61.8% (21/34) in the electroacupuncture group, which was superior to 19.4 (6/31) in the Erbium laser group (P<0.01). CONCLUSION: Both electroacupuncture at "four points of sacral region" and transurethral Erbium laser can improve the clinical symptoms and the quality of life in patients of moderate to severe stress urinary incontinence after radical prostatectomy. The short-term efficacy and long-term efficacy of electroacupuncture are superior to the Erbium laser technology.

Investigating the possibility of extending the BWR cycle length for 15 years of operation by mixing highly enriched UO2 fuel with burnable absorbers.

This paper investigates the possibility to extend the cycle length of boiling water reactor bundles to 15 years of operation with three different burnable poisons; gadolinium, erbium, and boron carbide. This can be carried out by mixing highly enriched UO2 fuel (15-19.9% U-235) with high concentrations of Gadolinium oxide (3-14% Gd2O3) or Erbium oxide (2-4% Er2O3).The boron carbide B4C was modeled as (Al2O3-B4C) rods in the bundle guide tubes. MCNPX code 2.7 was used to evaluate infinite multiplication factor (K-inf), power distribution, peaking factor, void reactivity coefficient, fuel cycle length, depletion of U-235, and fissile inventory ratio for the three designs at 40% void. The MCNPX simulation showed that introducing gadolinium rods at the bundle periphery has the advantage of lowering reactivity swing throughout the exposure range. The uniform distribution of erbium in all fuel rods contributed to the flattening of peaking factor at all the burnup stages. For the B4C design, the author found that the assembly with B4C-Al performs best in terms of reactivity flattening when five of the B4C-AL2O3 rods are positioned in the central region of the assembly. Furthermore, the fuel temperature coefficient is more negative for gadolinium design at all burnup stages. On the other hand, the boron model delivers the lowest control rod worth. Finally, the moderator temperature coefficient is more negative for erbium and WABA designs due to the enhanced thermal neutrons capture by the effect of the strategic arrangement of WABA rods and the uniform distribution of erbium.

Clinical observation on electroacupuncture at "four points of sacral region" on moderate to severe stress urinary incontinence after radical prostatectomy / 中国针灸

OBJECTIVE@#To compare the clinical therapeutic effect between electroacupuncture at "four points of sacral region" and transurethral Erbium laser in treatment of moderate to severe stress urinary incontinence after radical prostatectomy.@*METHODS@#A total of 68 patients of moderate to severe stress urinary incontinence after radical prostatectomy were divided into an electroacupuncture group (34 cases) and an Erbium laser group (34 cases, 3 cases dropped off) according to the settings. In the electroacupuncture group, electroacupuncture was applied at "four points of sacral region", i.e. points of 0.5 cun beside bilateral sacrococcygeal joints and bilateral Huiyang (BL 35), with continuous wave, 2 Hz in frequency, 60 min each time, once every other day, 3 times a week, 12 times as one course of treatment. In the Erbium laser group, transurethral Erbium laser technology was given, once every 4 weeks as one course of treatment. Both groups were treated for 5 courses. The scores of the International Consultation on Incontinence questionnaire-short form (ICI-Q-SF) and the incontinence quality of life questionnaire (I-QOL) were observed before treatment, after each course of treatment and in follow-up after 1 and 2 months of treatment completion, respectively, and the clinical efficacy was evaluated after treatment in the two groups.@*RESULTS@#Compared with those before treatment, the ICI-Q-SF scores were decreased while the I-QOL scores were increased after 5 courses of treatment and in follow-up after 1, 2 months of treatment completion in the two groups (P<0.01). The ICI-Q-SF score in follow-up after 2 months of treatment completion were higher than that after 5 courses of treatment in the Erbium laser group (P<0.05). After 3, 4, 5 courses of treatment and in follow-up after 1 and 2 months of treatment completion, the ICI-Q-SF scores in the electroacupuncture group were lower than those in the Erbium laser group (P<0.05, P<0.01); after 2, 3, 4, 5 courses of treatment and in follow-up after 1 and 2 months of treatment completion, the I-QOL scores in the electroacupuncture group were higher than those in the Erbium laser group (P<0.01). The change ranges of ICI-Q-SF score and I-QOL score between before treatment and after each course of treatment in the electroacupuncture group were lager than those in the Erbium laser group (P<0.01, P<0.05). The total effective rate was 61.8% (21/34) in the electroacupuncture group, which was superior to 19.4 (6/31) in the Erbium laser group (P<0.01).@*CONCLUSION@#Both electroacupuncture at "four points of sacral region" and transurethral Erbium laser can improve the clinical symptoms and the quality of life in patients of moderate to severe stress urinary incontinence after radical prostatectomy. The short-term efficacy and long-term efficacy of electroacupuncture are superior to the Erbium laser technology.

Innovative construction of a novel lanthanide cerate nanostructured photocatalyst for efficient treatment of contaminated water under sunlight.

Herein, we have developed Ln2Ce2O7 (Ln = Er, Ho) ceramic nanostructures through a rapid and green sonochemical approach and scrutinized their photocatalytic efficiency toward degradation of toxic pollutants under sunlight. Salvia rosmarinus extract is utilized as a morphology-directing agent in the sono-synthesis of the nanostructured Ln2Ce2O7 (Ln = Er, Ho), for the first time. Comprehensive characterization utilizing different techniques demonstrated that introducing of rare-earth metals, erbium and holmium, affected the textural, morphological, and optical features of the nanostructured ceria. The energy gap for pure cerium dioxide nanostructure was estimated to be 3.09 eV, while the energy gap for Ho2Ce2O7 and Er2Ce2O7 nanostructure was estimated at 2.9 and 2.66 eV, respectively. The narrowing of the energy gap was observed as a result of the introduction of rare-earth metals, erbium and holmium, especially erbium, into the nanostructured ceria. Investigation of the photocatalytic decomposition of various contaminants revealed that the introduction of erbium has remarkably enhanced the photocatalytic activity of nanostructured ceria. High photocatalytic performance (98.9%) and rate constant (0.0727 min-1) was observed for the Er2Ce2O7 nanostructure in the removal of eriochrome Black T. Improving the optical features of ceria nanostructure as well as enhancing its specific area were reasons that could increase the photocatalytic efficiency. The photocatalytic decomposition reactions in the removal of toxic contaminants were well accorded with the Pseudo-first order reaction kinetics. Besides, the nanostructured Er2Ce2O7 maintained its efficiency after ten reaction cycles and did not denote any notable decline in efficiency. The use of this novel porous nanostructure can be a potentially efficient solution for water treatment.

Improvement of apical papilla cell attachment after erbium, chromium-doped yttrium, scandium, gallium, and garnet laser application: a study in an ex vivo immature tooth model.

The purposes of this study were (1) to investigate the direct effect of an Er,Cr:YSGG laser on human apical papilla cell (APC) proliferation and mineralization and (2) to examine the effect of Er,Cr:YSGG laser, when applied to an ex vivo immature tooth model, on APC attachment. An Er,Cr:YSGG laser at various power outputs (0.1, 0.5, and 1 W) was used at different positions (2, 5, or 8 mm from the cells) to irradiate cultured APCs. APC proliferation and mineralization were assessed at various intervals. For the cell attachment evaluation, ex vivo tooth models containing dentin samples were irrigated with either EDTA or normal saline solution (NSS) and supplemented with laser activation. Fibronectin-positive-staining cells were counted and analyzed. The number of APCs was significantly greater when power outputs of 0.1 W and 0.5 W were used than when 1 W was used (P < 0.05). The close contact of laser application, at 2 and 5 mm, exerted a negative effect on cell proliferation at 24 and 48 h. The application at 8 mm did not show the deterioration effect. APC mineralization was reduced after laser irradiation, regardless of the power and the tip positioning, at 21 days. APC attachment in all laser-activated groups was significantly greater than in the groups without laser. The use of Er,Cr:YSGG laser significantly promoted APC attachment on the root canal dentin.

A split-face comparison of fractional erbium: YAG laser plus Kligman's formula vs. Kligman's formula monotherapy for facial melasma.

Melasma is a chronic hyperpigmentation disorder. Although several treatment methods are used for patients, it remains a challenging problem for physicians. Erbium-YAG laser is one of the laser treatment methods that proved its efficacy in melasma treatment. We aimed to compare the efficacy of combining the fractional Er: YAG laser and Kligman's formula with Kligman's formula alone in the treatment of melasma. Twenty female patients with bilateral melasma were randomly treated in a split-face controlled manner with a fractional Er: YAG laser followed by Kligman's formula on one side and Kligman's formula on the other side. All patients received three laser sessions with four-week intervals. The efficacy of treatments was determined through photographs, Visioface, and Melasma Area Severity Index (MASI) score, all performed at baseline and three months after the end of laser sessions. Fractional Er: YAG laser and Kligman's formula showed a significant decrease in MASI score than Kligman's formula alone (P = 0.005). There was a significant decrease in cheek Visioface score on Er: YAG laser and Kligman's formula vs Kligman's formula (P = 0.02). However, the Patient Global Assessment Scale of both sides was not statistically significant (P = 0.23). The combination of Fractional Er: YAG laser with Kligman's formula is an effective treatment method for melasma.

Fractional erbium:YAG laser (2940 nm) plus topical hydroquinone compared to intradermal tranexamic acid plus topical hydroquinone for the treatment of refractory melasma: a randomized controlled trial.

OBJECTIVES: Melasma is a chronic acquired condition characterized by grayish-brown macules and patches with a distinct border on the face. Although various treatments methods have been suggested for treating melasma, none has been completely successful. The aim of the study was to compare the efficiency of erbium: yttrium-aluminum-garnet (Er:YAG) laser and 4% hydroquinone (HQ) with the effects of intradermal tranexamic acid (TA) and 4% HQ for the treatment of refractory melasma. METHODS: The study included 31 female patients with refractory melasma. The left or right side of the patient's face was chosen randomly to receive laser therapy with topical HQ on the one side (i.e. the laser side) and intradermal injection of TA plus topical HQ on the other side (i.e. the mesotherapy side). Digital photography was performed at baseline, at the end of the treatment, and three months after the treatment as follow-up. Two independent dermatologists evaluated the modified Melasma Area and Severity Index (mMASI) score according to the pictures. Overall, 27 patients completed the study and went through the clinical evaluation. RESULTS: Treatment using HQ in combination with either Er:YAG laser therapy or intradermal injection of TA significantly improved the hemi-mMASI and resulted in higher patient satisfaction. While the improvement was not significantly different between the two regiments after the treatment and upon follow up and both were equally efficient in the treatment of refractory melasma (p = 1.308), recurrence rate was higher after treatment with Er:YAG laser than TA (12% vs 34%). CONCLUSION: This study confirmed the comparable efficacy of TA plus topical HQ versus Er:YAG laser plus topical HQ for the treatment of refractory melasma. Both groups improved significantly and no subject left the treatment because of adverse effects. TRIAL REGISTRATION NUMBER: IRCT20191011045057N1.

Comparative appraisal with meta-analysis of erbium vs. CO2 lasers for atrophic acne scars.

Recent advances in laser technology allowed the development of systems that improve texture, appearance and pliability of skin in acne scars (AS). Currently, comprehensive comparative studies on the efficacy of the most commonly used fractional systems in AS are lacking. Thus, the aim of this work was to appraise and compare the clinical response to erbium versus CO2 lasers in AS in the form of a meta-analysis. The databases MEDLINE, EMBASE, Cochrane library were searched. Main clinical outcomes were investigator-reported scar improvement and participant-reported scar improvement. Five studies were included in this meta-analysis. Scar improvement was similar for both types of laser in terms of investigator-reported scar improvement (RR: 0.60 95 % CI: 0.35-1.02) and participant-reported scar improvement (RR: 0.99 95 % CI: 0.79-1.25). A sensitivity analysis that excluded studies with high risk of bias found the CO2 lasers to be superior to the erbium lasers (RR: 0.47 95 % CI: 0.24-0.93): However, the subgroup analysis showed the CO2 laser not to be significantly different from either the non-ablative erbium (RR: 0.65 95 % CI: 0.34-1.24) or the ablative erbium laser (RR: 0.60 95 % CI: 0.35-1.02). The CO2 laser produced a slightly greater clinical response compared to the erbium lasers based on the physician's assessment. Overall, the two devices do not differ largely in terms of efficacy but may be complementary, with each resurfacing laser better suited for different clinical tasks.

Safety and Efficacy of High-Dose Fractional Erbium: Yttrium Aluminium Garnet Laser in Stable Vitiligo.

Objective: Evaluate the treatment outcome of vitiligo patients receiving a standard regimen of high-dose biweekly fractional 2940 nm erbium:yttrium aluminium garnet (YAG) laser applications as an add-on to various treatment modalities. Materials and methods: The authors extracted the study population's clinical images before treatment and 3rd-month control from their clinical archive and used the medical records. The primary outcome measure was 50% repigmentation at 3rd-month follow-up. Institutional ethical committee approved the study. Results: Of the evaluated 28 patients, 18 were eligible with 31 treatment regions. All patients received at least one topical agent [steroids, calcineurin inhibitors, or 5-fluorouracil (5-FU)] and 11 patients received either targeted ultraviolet B (UVB) or narrow-band UVB. Of the 31 study regions, 88.8% (8/9) of facial; 77.7% (7/9) of dorsal hand; 75% (3/4) of limb; and 25% (2/8) of finger lesions achieved 50% repigmentation at 3rd-month control. The facial and dorsal hand lesions' treatment responses were higher than finger lesions (p = 0.008 and 0.03, respectively). Upon evaluating adjuvant treatment modalities, all of the treatment regions receiving targeted UVB (n = 4) or topical 5-FU (n = 5) achieved the primary endpoint, whereas severe irritation limited the topical use of 5-FU. The most common adverse effects were mild oozing and crusting related to laser treatments. Conclusions: Even with high-energy settings, fractional erbium: YAG laser does not induce the Koebner phenomenon. Although controlled trials are required to make firm conclusions, fractional erbium: YAG laser was an effective and safe adjunctive option for stable vitiligo in a real-life setting.

The pH responsive upconversion fluorescence and photothermal conversion properties of NaYF4:Yb3+/Er3+@NaYF4@MnO2@Au.

While photothermal therapy is widely applied in phototherapy, there are still challenges in developing new generation phototherapy materials with precise diagnostic functions. Here we report the construction of a pH responsive upconversion fluorescence imaging precisely guided photothermal therapy system, namely NaYF4:Yb3+/Er3+@NaYF4@MnO2@Au nanocomposites, which can effectively avoid light damage to non-target tissues. Owing to the fluorescence resonance energy transfer between the upconversion nanocrystal donor and MnO2 and Au acceptor, the upconversion fluorescence is completely quenched. However, in pH 5.3 PBS buffer, MnO2 is gradually broken down, and the upconversion fluorescence is partially recovered, which could be used for upconversion fluorescence imaging to precisely guide photothermal therapy under 980 nm excitation. Simultaneously, due to the absorption of 980 nm excitation light and the emission bands of Er3+ (2H11/2→4I15/2 and 4S3/2→4I15/2 transition), temperature increment of core@shell@MnO2@Au could reach 35.5 °C under 980 nm excitation at 0.8 W cm-2. The core@shell@MnO2@Au nanocomposites are supposed to contribute significantly in the biological applications of photoluminescence imaging and photothermal therapy.

Bactericidal effect of Er,Cr:YSGG laser irradiation on endodontic biofilm: An ex vivo study.

AIM: This ex vivo study aimed to evaluate the of Er,Cr:YSGG laser effectiveness in the decontamination of an endodontic biofilm. MATERIALS AND METHODS: Seventy-three single rooted human teeth, freshly were chosen. Each tooth was exposed to four associated species in an endodontic biofilm (Enterococcus faecalis, Streptococcus salivarius, Porphyromonas gingivalis, and Prevotella intermedia) and randomly allocated to one of the seven experimental groups. The group 1 (7 teeth) was used to finalize the reliable biofilm-forming technique. The groups 2 and 3 (15 teeth each group) were irradiated with two different Er;Cr:YSGG laser settings (0,75 W - 40 Hz and 4 W - 40 Hz, respectively). The groups 4 and 5 (15 teeth each group) were irrigated with two different solutions and laser irradiated with the same settings (1,5 W - 15 Hz). The group 6 (6 teeth) was the control group treated only with 4 ml 2,5% NaOCl irrigation during 60 s. RESULTS: The observations of group 2 and 3 specimens showed the ripeness of the biofilm with the presence of Enterococcus faecalis and Streptococcus salivarius in chains but in group 3 thermal edge effects produced by the optic fiber in the canal walls were present. The group 4 specimens observation showed an average cleaning of the root canal walls while on the canal walls of group 5 samples the apical third presented several debris and smear layer and in the centre cracks and melting dentin of the radicular wall were observed. CONCLUSION: In those experimental conditions, this study, demonstrated that Er,Cr:YSGG laser has a canals decontamination ability when associated to NaOCl irrigation.

Semiquantitative immunochromatographic colorimetric biosensor for the detection of dexamethasone based on up-conversion fluorescent nanoparticles.

A low-cost bifunctional immunochromatographic colorimetric biosensor was developed that can be read visually or by using an optical density scanner. Five test lines (T lines) coated with different antigens were set on a nitrocellulose (NC) membrane to indicate the concentration of analyte. This method was applied for the detection of dexamethasone. The corresponding detection range was 0.1-9 ng mL-1, and the detection limit for dexamethasone in food supplements and cosmetic samples was 2.0 µg kg-1. For visual inspection of the colour the quantitative relative error range between the proposed method and liquid chromatography was -62 to -25%, with a detection time of only 10 min. More accurate assay results were obtained by using an optical density scanner with the relative error range of -31 to 20%. The results indicated that the proposed method has the potential of application for rapid and efficient screening of dexamethasone in cosmetics and food supplements. Graphical abstract.

Unmodified Rose Bengal photosensitizer conjugated with NaYF4:Yb,Er upconverting nanoparticles for efficient photodynamic therapy.

In photodynamic therapy (PDT), photosensitizer (PS) molecules are irradiated by light to generate reactive oxygen species (ROS), the presence of which subsequently leads to cell death. At present, the modality is limited to the treatment of skin diseases because of the low tissue penetration of visible or ultraviolet light required for producing ROS. To increase tissue penetration and extend the therapeutic possibilities of PDT to the treatment of deep-seated cancer, rare-earth doped nanoparticles capable of up-converting infrared to visible light are investigated. These up-converting nanoparticles (UCNPs) are conjugated with PS molecules to efficiently generate ROS. In this work, we employ hexagonal ß-NaYF4:Yb3 + ,Er3 + as UCNPs and Rose Bengal (RB) as PS molecules and demonstrate efficient in vitro PDT using this nanoformulation. Covalent bonding of the RB molecules is accomplished without their functionalization-an approach which is expected to increase the efficiency of ROS generation by 30%. Spectroscopic studies reveal that our approach results in UCNP surface fully covered with RB molecules. The energy transfer from UCNPs to RB is predominantly non-radiative as evidenced by luminescence lifetime measurements. As a result, ROS are generated as efficiently as under visible light illumination. The in vitro PDT is tested on murine breast 4T1 cancer cells incubated with 250 µg ml-1 of the nanoparticles and irradiated with NIR light under power density of 2 W cm-2 for 10 minutes. After 24 hours, the cell viability decreased to 33% demonstrating a very good treatment efficiency. These results are expected to simplify the protocols for preparation of the PDT agents and lead to improved therapeutic effects.

NaGdF4:Yb,Er-Ag nanowire hybrid nanocomposite for multifunctional upconversion emission, optical imaging, MRI and CT imaging applications.

The effect of novel silver nanowire encapsulated NaGdF4:Yb,Er hybrid nanocomposite on the upconversion emission and bioimaging properties has been investigated. The upconvension nanomaterials were synthesised by polyol method in the presence of ethylene glycol, PVP and ethylenediamine. The NaGdF4:Yb,Er-Ag hybrid was formed with upconverting NaGdF4:Yb,Er nanoparticles of size ~ 80 nm and silver nanowires of thickness ~ 30 nm. The surface plasmon induced by the silver ion in the NaGdF4:Yb,Er-Ag nanocomposite resulted an intense upconversion green emission at 520 nm and red emission at 660 nm by NIR diode laser excitation at 980 nm wavelength. The UV-Vis-NIR spectral absorption at 440 nm and 980 nm, the intense Raman vibrational modes and the strong upconversion emission results altogether confirm the localised surface plasmon resonance effect of silver ion in the hybrid nanocomposite. MRI study of both NaGdF4:Yb,Er nanoparticle and NaGdF4:Yb,Er-Ag nanocomposite revealed the T1 relaxivities of 22.13 and 10.39 mM-1 s-1, which are larger than the commercial Gd-DOTA contrast agent of 3.08 mM-1 s-1. CT imaging NaGdF4:Yb,Er-Ag and NaGdF4:Yb,Er respectively showed the values of 53.29 HU L/g and 39.51 HU L/g, which are higher than 25.78 HU L/g of the CT contrast agent Iobitridol. The NaGdF4:Yb,Er and NaGdF4:Yb,Er-Ag respectively demonstrated a negative zeta potential of 54 mV and 55 mV, that could be useful for biological application. The in vitro cytotoxicity of the NaGdF4:Yb,Er tested in HeLa and MCF-7 cancer cell line by MTT assay demonstrated a cell viability of 90 and 80 %, respectively. But, the cell viability of NaGdF4:Yb,Er-Ag slightly decreased to 80 and 78%. The confocal microscopy imaging showed that the UCNPs are effectively up-taken inside the nucleolus of the cancer cells, and it might be useful for NIR laser-assisted phototherapy for cancer treatment. Graphical abstract.

Self-Sufficient and Highly Efficient Gold Sandwich Upconversion Nanocomposite Lasers for Stretchable and Bio-applications.

Multifunctional lanthanide-doped upconversion nanoparticles (UCNPs) have spread their wings in the fields of flexible optoelectronics and biomedical applications. One of the ongoing challenges lies in achieving UCNP-based nanocomposites, which enable a continuous-wave (CW) laser action at ultralow thresholds. Here, gold sandwich UCNP nanocomposites [gold (Au1)-UCNP-gold (Au2)] capable of exhibiting lasing at ultralow thresholds under CW excitation are demonstrated. The metastable energy-level characteristics of lanthanides are advantageous for creating population inversion. In particular, localized surface plasmon resonance-based electromagnetic hotspots in the nanocomposites and the huge enhancement of scattering coefficient for the formation of coherent closed loops due to multiple scattering facilitate the process of stimulated emissions as confirmed by theoretical simulations. The nanocomposites are subjected to stretchable systems for enhancing the lasing action (threshold ∼ 0.06 kW cm-2) via a light-trapping effect. The applications in bioimaging of HeLa cells and antibacterial activity (photothermal therapy) are demonstrated using the newly designed Au1-UCNP-Au2 nanocomposites.

Molecular Antenna-Sensitized Upconversion Nanoparticle for Temperature Monitored Precision Photothermal Therapy.

BACKGROUND: Photothermal therapy with accurate and real-time temperature detection is desired in clinic. Upconversion nanocrystals (UCNs) are candidate materials for simultaneous temperature detection and photothermal agents carrying. However, the weak luminescence and multiple laser excitations of UCNs limit their application in thermal therapy. MATERIALS AND METHODS: NaYF4:Yb3+,Er3+,Nd3+, PL-PEG-NH2, IR-806 and folic acid are selected as structural components. A nanoprobe (NP) integrated with efficient photothermal conversion and sensitive temperature detection capabilities is synthesized for precise photothermal therapy. The probes are based on near-infrared upconversion nanocrystals doped with Yb, Er and Nd ions, which can be excited by 808 nm light. IR-806 dye molecules are modified on the surface as molecular antennas to strongly absorb near-infrared photons for energy transfer and conversion. RESULTS: The results show that under an 808 nm laser irradiation upconversion luminescence of the nanocrystals is enhanced based on both the Nd ion absorption and the FRET energy transfer of IR-806. The luminescence ratio at 520 and 545 nm is calculated to accurately monitor the temperature of the nanoparticles. The temperature of the nanoprobes increases significantly through energy conversion of the molecular antennas. The nanoparticles are found successfully distributed to tumor cells and tumor tissue due to the modification of the biocompatible molecules on the surface. Tumor cells can be killed efficiently based on the photothermal effect of the NPs. Under the laser irradiation, temperature at mouse tumor site increases significantly, tissue necrosis and tumor cell death can be observed. CONCLUSION: Precision photothermal therapy can thus be achieved by highly efficient near-infrared light absorption and accurate temperature monitoring, making it promising for tumor treatment, as well as the biological microzone temperature detection.

Sextuple ratiometric thermometry based on 980-nm-upconverted green fluorescence of Er3+ ions in submicron crystals.

980-nm-upconverted 530 and 550 nm Er3+ green fluorescence spectra of Er3+/Yb3+-codoped NaGd(WO4)2 submicron crystals were measured in the temperature range of 298-383 K. A sextuple ratiometric thermometry is proposed. It is established on the basis of six schemes of fluorescence intensity ratio (FIR) that considers three component peaks of the 530 nm emission band and two component peaks of the 550 nm emission band, which involve electronic transitions between two Stark sublevels of Er3+. The study shows that the phosphor shows strong green fluorescence, which is verified by measured quantum yield, and thermally stable spectral structure desired for the sextuple ratiometric thermometry. All of the six FIR schemes display highly efficient sensing performances with slightly different thermal sensitivities. Each scheme gives a temperature value and the six schemes give an averaged result. In parallel, we have also carried out an ex vivo experimental study on the temperature characteristics of the green fluorescence of the phosphor. Almost same results have been obtained, verifying biological applicability of the phosphor. The ex vivo experimental results also show that the sextuple thermometry increases considerably the accuracy and reliability of temperature measurement in comparison with the conventional intensity integration method.

Real-Time Monitoring of Temperature Variations around a Gold Nanobipyramid Targeted Cancer Cell under Photothermal Heating by Actively Manipulating an Optically Trapped Luminescent Upconversion Microparticle.

We demonstrate an effective approach to realize active and real-time temperature monitoring around the gold nanobipyramids (AuNBPs)-labeled cancer cell under 808 nm laser irradiation by combining optical tweezers and temperature-sensitive upconversion microparticles (UCMPs). On the one hand, the aptamer-modified AuNBPs that absorb laser at 808 nm not only act as an excellent photothermal reagent but also accurately and specifically bind the target cancer cells. On the other hand, the single optically trapped NaYF4:Yb3+, Er3+ UCMPs with a 980 nm laser exhibit temperature-dependent luminescence properties, where the intensity ratio of emission 525 and 547 nm varies with the ambient temperature. Therefore, real-time temperature variation monitoring is performed by 3D manipulation of the trapped single UCMP to control its distance from the AuNBPs-labeled cancer cell while being photothermally killed. The results show distance-related thermal propagation because the temperature increase reaches as high as 10 °C at a distance of 5 µm from the cell, whereas the temperature difference drops rapidly to 5 °C when this distance increases to 15 µm. This approach shows that the photothermal conversion from AuNBPs is sufficient to kill the cancer cells, and the temperature increase can be controlled within the micrometer level at a certain period of time. Overall, we present a micrometer-size thermometer platform and provide an innovative strategy to measure temperature at the micrometer level during photothermal killing of cancer cells.