Lignin as a MALDI matrix for small molecules: a proof of concept.

Driven by the interest in metabolomic studies and the progress of imaging techniques, small molecule analysis is booming, while it remains challenging to be realized by matrix-assisted laser desorption/ionization mass spectrometry (MALDI-MS). Herein, lignin, the second most abundant biomass in nature, was applied as a dual-ion-mode MALDI matrix for the first time to analyze small molecules. The low ionization efficiency and strong optical absorption properties make lignin a potential MALDI matrix in small molecule analysis. A total of 30 different small molecules were identified qualitatively and six kinds of representative molecules were detected quantitatively with a good linear response (R2 > 0.995). To verify the accuracy of our quantitative method in MALDI, myricitrin, a major bioactive component in Chinese bayberry, was analyzed in different cultivars and tissues. The myricitrin content in real samples detected by MALDI was highly consistent (R2 > 0.999) with that detected by high-performance liquid chromatography, thus indicating the applicability of the lignin matrix. Further characterization by ultraviolet and nuclear magnetic resonance spectroscopy was carried out to explain the possible mechanism of lignin as a matrix and provide more theories for a rational matrix design.

Surface plasmon resonance assay for exosomes based on aptamer recognition and polydopamine-functionalized gold nanoparticles for signal amplification.

A novel surface plasmon resonance (SPR) strategy is introduced for the specific determination of exosomes based on aptamer recognition and polydopamine-functionalized gold nanoparticle (Au@PDA NP)-assisted signal amplification. Exosomes derived from hepatic carcinoma SMMC-7721 were selected as the model target. SMMC-7721 exosomes can be specifically captured by the aptamer ZY-sls that was complementary to the DNA tetrahedron probes (DTPs), and then the CD63 aptamer-linked Au@PDA NPs recognized SMMC-7721 exosomes for signal amplification. The DTPs were modified on a Au film for preventing Au deposition on the surface during the introduction of HAuCl4, and PDA coated on the AuNPs was used to reduce HAuCl4 in situ without any reductant assistance. It results in a further enhanced SPR signal. The assay can clearly distinguish SMMC-7721 exosomes from others (HepG2 exosomes, Bel-7404 exosomes, L02 exosomes, MCF-7 exosomes, and SW480 exosomes, respectively). SMMC-7721 exosomes are specifically determined as low as 5.6 × 105 particles mL-1. The method has successfully achieved specific determination of SMMC-7721 exosomes even in 50% of human serum without any pretreatment. Graphical abstract A novel surface plasmon resonance (SPR) strategy was introduced for the specific determination of exosomes based on aptamer recognition and polydopamine functionalized gold nanoparticles (Au@PDA NPs). The SPR signal was improved using the Au@PDA NPs assisted amplification.

Colorimetric determination of glutathione in human serum and cell lines by exploiting the peroxidase-like activity of CuS-polydopamine-Au composite.

In this study, we developed a simple colorimetric approach to detect glutathione (GSH). The proposed approach is based on the ability of CuS-PDA-Au composite material to catalytically oxidize 3,3',5,5'-tetramethylbenzidine (TMB) to ox-TMB to induce a blue color with an absorption peak centered at 652 nm. However, the introduction of GSH can result in a decrease in oxidized TMB; similarly, it can combine with Au nanoparticles (Au NPs) on the surface of CuS-PDA-Au composite material. Both approaches can result in a fading blue color and a reduction of the absorbance at 652 nm. Based on this above, we proposed a technique to detect GSH quantitatively and qualitatively through UV-Vis spectroscopy and naked eye, respectively. This approach demonstrates a low detection limit of 0.42 µM with a broad detection range of 5 × 10-7-1 × 10-4 M with the assistance of UV-Vis spectroscopy. More importantly, this approach is convenient and rapid. This method was successfully applied to GSH detection in human serum and cell lines. Graphical abstract A colorimetric approach has been developed by exploiting the peroxidase-like activity of CuS-polydopamine-Au composite for sensitive glutathione detection.

Fluorescence and magnetic nanocomposite Fe3O4@SiO2@Au MNPs as peroxidase mimetics for glucose detection.

In this paper, multifunction nanoparticles (MNPs), Fe3O4@SiO2@Au MNPs, with properties of superparamagnetism, fluorescence and peroxidase-like catalytic activity were synthesized in the aqueous phase. The synthesized composites were characterized by scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD), Fourier translation infrared spectrum (FT-IR) and fluorometer. The results show that the multifunctional nanomaterials have good magnetic and fluorescence properties. Then, the mimetic properties of this material were investigated. The as-synthesized Fe3O4@SiO2@Au MNPs exhibited the best catalytic activity for peroxidase substrate 3,3,5,5-tetramethylbenzidine (TMB) at the reaction temperature of 70 °C and pH of 3. Compared with free Fe3O4 MNPs and BSA-Au nanoclusters (NCs), the composites have better catalytic activity at higher temperature and lower pH, indicating that Fe3O4@SiO2@Au MNPs can work in more severe environment. In practical application, we have successfully established the colorimetric method for the detection of H2O2 and glucose with the detection range of 1 × 10-6 ∼ 4 × 10-5 M and 5 × 10-6 ∼ 3.5 × 10-4 M, and the detection limit of 6 × 10-7 M and 3.5 × 10-6 M, respectively. The method was also successfully applied in the detection of real samples. Furthermore, since the fluorescence of Fe3O4@SiO2@Au MNPs was quenched by H2O2, a method for the visual detection of glucose was established.

Preliminary efficacy and safety of a silicone oil-filled foldable capsular vitreous body in the treatment of severe retinal detachment.

PURPOSE: We previously invented a novel foldable capsular vitreous body (FCVB) in the treatment of severe retinal detachment. The purpose of this study was to determine its hydrolytic stability in vitro and further evaluate its efficacy and safety in human eyes. METHODS: The hydrolytic stability test proceeded according to State Food and Drug Administration guidelines about intraocular lenses of the ophthalmic implants. A standard three-port pars plana vitrectomy was performed, and FCVB was triple folded and sent into the vitreous cavity of three eyes; then silicone oil was injected into the capsule to support the retina. The treated eyes were examined using Goldmann applanation tonometry, fundus photography, optical coherence tomography, noncontact specular microscopy, and ultrasound biomicroscopy during a 12-month follow-up appointment. RESULTS: The mass of FCVB with silicone oil after 60-day accelerating aging temperature was equal to that at baseline. The FCVB can easily be implanted into the vitreous cavity through a 3-mm incision. The visual acuity and intraocular pressure after FCVB implantation show a slight elevation compared with those of preoperative eyes. The fundus and optical coherence tomography showed that the FCVB was well distributed in the vitreous cavity and evenly supported the retina. Retinal reattachment was found in 3 eyes at the 12-month examination. There was no statistically significant decrease in the density of corneal endothelial cells from baseline to 12 months after FCVB implantation. Ultrasound biomicroscopy showed that the FCVB smoothly contacted but not crushed the ciliary body. CONCLUSION: Silicone oil-filled FCVB was shown to be effective and safe in 3 eyes as a vitreous substitute over a 12-month observation time.

Biocompatibility and retinal support of a foldable capsular vitreous body injected with saline or silicone oil implanted in rabbit eyes.

INTRODUCTION: The aim of this study was to evaluate over a 180-day period the biocompatibility and retinal support of a foldable capsular vitreous body injected with either saline or silicone oil implanted in rabbit eyes. METHODS: A standard three-port pars plana vitrectomy was performed, and foldable capsular vitreous bodies were implanted into the vitreous cavity of rabbit eyes (n = 18). Silicone oil tamponade was used as the control group (n = 5). Of the foldable capsular vitreous body-implanted eyes, either saline (n = 9) or silicone oil (n = 9) was injected into the foldable capsular vitreous body to support the retina. The treated eyes were examined using a slit lamp with a non-contact slit-lamp lens, a tonopen, a non-contact specular microscope and a B-scan ultrasound during the 180-day implantation period. A histological examination was performed at 90 and 180 days. RESULTS: During the 180-day implantation period, no significant corneal keratopathy or intraocular inflammation was noted, and the intraocular pressure (IOP) and corneal endothelial numbers remained steady among the three groups. B-scan ultrasonography showed a smoothly increased echogenicity in front of the retina in group of foldable capsular vitreous bodies injected with saline. Gross examination showed that the foldable capsular vitreous bodies injected with saline or silicone oil smoothly supported the retina. The saline or silicone oil inside the foldable capsular vitreous body was homogeneous, transparent and filled the foldable capsular vitreous body. Histological examination showed no obvious abnormality of the cornea, ciliary body or retina in the foldable capsular vitreous body-implanted eyes. CONCLUSIONS: These results suggest that foldable capsular vitreous bodies injected with either saline or silicone oil showed good biocompatibility and retinal support in rabbit eyes over a 180-day implantation time.

Technical standards of a foldable capsular vitreous body in terms of mechanical, optical, and biocompatible properties.

We previously proposed a new strategy to fabricate a novel foldable capsular vitreous body (FCVB) as a vitreous substitute and found that the FCVB was a very good replacement for closely mimicking the morphology and restoring the physiologic function of the rabbit vitreous body. The aim of this article was to assess the mechanical, optical, and biocompatible properties of a FCVB made from liquid silicone rubber. The mechanical properties show that the shore hardness is 37.80 degrees, the tear strength is 47.14 N/mm, the tensile strength is more than 7.28 MPa, and the elongation ratio is more than 1200%; in addition, the FCVB has 300 nm mili apertures in the capsule. The optical properties reveal that transmittances are 92%, hazes are 5.74%, and spectral transmittance is 97%. The transmittance mission is 2.3% and can sustain a 1500 mW, 0.2 s, 532 nm green laser. The biocompatible properties are shown in the stable extracts experiment, no significant fever, good genetic safety, and no structural abnormality or apoptosis in the cornea, ciliary body, and retina over a 6-month observation period. These results indicate that the FCVB has good mechanical, optical, and biocompatible properties, and the assessment results can be recommended as the FCVB technical standards for industrial manufacturing and inspection.

Construction of Bio/Nanointerfaces: Stable Gold Nanoparticle Bioconjugates in Complex Systems.

The real application of DNA-functionalized gold nanoparticles (DNA-Au NPs) was limited by decreased stability and irreversible aggregation in high-ionic strength solutions and complex systems. Therefore, exploring a kind of DNA-Au NPs with excellent stability in high-ionic strength solutions and complex systems is challenging and significant. Herein, a novel universal bioconjugate strategy for constructing ultrastable DNA-Au NPs was designed based on the combination of polydopamine (PDA) shell and DNA linker. The obtained DNA-linked Au@polydopamine nanoparticles (DNA-Au@PDA NPs) showed colloidal stability in high-ionic strength solution and complex systems (such as human serum and cell culture supernatant). Moreover, the nanoparticles still maintained good dispersion after multiple freeze-thaw cycles. The high stability of DNA-Au@PDA NPs may be attributed to increasing the electrostatic and steric repulsions among nanoparticles through the effect of both PDA shell and DNA linker on Au@PDA NPs. For investigating the application of such nanoparticles, a highly sensitive assay for miRNA 141 detection was developed using DNA-Au@PDA NPs coupled with dynamic light scattering (DLS). Comparing with the regular DNA-Au NPs, DNA-Au@PDA NPs could detect as low as 50 pM miRNA 141 even in human whole serum. Taken together, the features of Bio/Nanointerface make the nanoparticle suitable for various applications in harsh biological and environmental conditions due to the stability. This work may provide a universal modification method for obtaining stable nanoparticles.

Lithium-containing biomaterials stimulate bone marrow stromal cell-derived exosomal miR-130a secretion to promote angiogenesis.

The chemical signals of biomaterials could influence bone marrow stromal cells (BMSCs)-endothelial cells (ECs) communication during vascularized bone regeneration. However, the underlying mechanisms still remain unknown. Exosomes, a series of extracellular vesicles, have recently emerged as potential paracrine mediators in cell-cell communication. However, whether exosomes and exosomal microRNAs (miRNAs) are involved in the chemical signals of biomaterials-modulated BMSCs-ECs communication are unknown. Hence, in the present study, a model Li-incorporated bioactive glass ceramic (Li-BGC) was applied to explore the chemical signals of biomaterials mediated cell-cell communication between BMSCs and ECs. Our results showed that Li-BGC directly promoted the pro-angiogenic capability of HUVECs in vitro and new blood vessel ingrowth in vivo. Moreover, Li-BGC activated Wnt/ß-catenin, AKT and NF-κB signaling pathways, while AKT signaling pathway might function as the upstream of Wnt/ß-catenin and NF-κB signaling pathways. More importantly, Li-BGC further facilitated the pro-angiogenic capacity of HUVECs by eliciting the expression of exosomal pro-angiogenic miR-130a in BMSCs-derived exosomes, which subsequently leading to the downregulation of PTEN protein and activation of AKT pathway, ultimately resulting in the elevated proliferation, migration and tube formation of endothelial cells, as well as the upregulated expression of pro-angiogenic genes. Our findings may provide new insights into the regulatory roles of the chemical signals of biomaterials in BMSCs-ECs communication via stimulating exosomal miR-130a secretion and PTEN/AKT signaling pathway in the angiogenic process of bone remodelling.

3D-printed scaffolds with bioactive elements-induced photothermal effect for bone tumor therapy.

For treatment of bone tumor and regeneration of bone defects, the biomaterials should possess the ability to kill tumor cells and regenerate bone defect simultaneously. To date, there are a few biomaterials possessing such dual functions, the disadvantages, however, such as long-term toxicity and degradation, restrict their application. Although bioactive elements have been incorporated into biomaterials to improve their osteogenic activity, there is no report about elements-induced functional scaffolds for photothermal tumor therapy. Herein, the elements (Cu, Fe, Mn, Co)-doped bioactive glass-ceramic (BGC) scaffolds with photothermal effect and osteogenic differentiation ability were prepared via 3D-printing method. Moreover, the photothermal anti-tumor effect and osteogenic activity of these scaffolds were systematically investigated. The prepared elements-doped scaffolds possessed excellent photothermal performance, which displayed a trend, 5Cu-BGC > 5Fe-BGC > 5Mn-BGC > 5Co-BGC, in this study. The final temperature of elements-doped scaffolds can be well controlled by altering the doping element categories, contents and laser power density. Additionally, the hyperthermia induced by 5Cu-BGC, 5Fe-BGC and 5Mn-BGC effectively killed tumor cells in vitro and inhibited tumor growth in vivo. More importantly, 5Fe-BGC and 5Mn-BGC scaffolds could promote rabbit bone mesenchymal stem cells (rBMSCs) adhesion, and the ionic products released from elements-doped scaffolds significantly stimulated the osteogenic differentiation of bone-forming cells. These results suggested that 5Fe-BGC and 5Mn-BGC scaffolds possessed promising potential for photothermal treatment of bone tumor and at the same time for stimulating bone regeneration, representing a smart strategy for the treatment of bone tumors by combining dual functional bioactive ions with tissue engineering scaffolds. STATEMENT OF SIGNIFICANCE: The major innovation of this study is that we fabricated the elements (Cu, Fe, Mn, Co)-doped bioactive scaffolds via 3D printing technique and found that they possess distinct photothermal performance and osteogenic differentiation ability. To the best of our knowledge, there is no report about elements-doped scaffolds for photothermal therapy of bone tumor. This is an important research advance by combining the photothermal effect and osteogenic differentiation activity of bioactive elements in the scaffold system for potential bone tumor therapy and bone reconstruction. We optimized the elements-doped scaffolds and found the photothermal effect of elements-doped scaffolds (5Cu-BGC, 5Fe-BGC, 5Mn-BGC) could effectively kill tumor cells in vivo. The photothermal performance of elements-doped scaffolds follows a trend: 5Cu-BGC > 5Fe-BGC > 5Mn-BGC > 5Co-BGC > BGC. Compared to traditional nano-sized photothermal agents, bioactive elements-induced functional scaffolds have better biosecurity and bioactivity. Furthermore, 5Fe-BGC and 5Mn-BGC scaffolds displayed excellent bone-forming activity by stimulating the osteogenic differentiation of bone-forming cells. The major significance of the study is that the elements-doped bioactive glass-ceramics (5Fe-BGC, 5Mn-BGC) have great potential to be used as bifunctional scaffolds for photothermal tumor therapy and bone regeneration, representing a smart strategy for the treatment of bone tumors by combining dual functional bioactive ions with tissue engineering scaffolds.

Preliminary study on retinal vascular and oxygen-related changes after long-term silicone oil and foldable capsular vitreous body tamponade.

Silicone oil has been the only long-term vitreous substitute used in the treatment of retinal detachment since 1962 by Cibis. Nevertheless, its effects on retinal vascular morphology and oxygen supply to the retina are ambiguous in current research. We previously invented a foldable capsular vitreous body (FCVB) to use as a new vitreous substitute in the treatment of severe retinal detachment, but its effects on the retinal vessel were unknown. Therefore, in this study, a standard three-port pars plana vitrectomy (PPV) was performed on the right eye of each rabbit and then silicone oil and FCVB were injected into the vitreous cavity as vitreous substitutes. After 180 days of retention, the retinal vascular morphology did not display any distinct abnormalities, and hypoxia-induced factor-1alpha (HIF-1α) and vascular endothelial growth factor (VEGF) did not vary markedly during the observation period in silicone oil tamponade- and FCVB-implanted eyes. This study may suggest that silicone oil and FCVB tamponade in rabbit eyes did not cause retinal vascular pathologic changes or retinal hypoxia for 180 days.

Functional evaluation of a novel vitreous substitute using polyethylene glycol sols injected into a foldable capsular vitreous body.

Polyethylene glycol (PEG) is a short-term (41 days) potential vitreous substitute and is too short for an ideal vitreous substitute. Previously, a foldable capsular vitreous body (FCVB) was designed to mimic vitreous function. The aim of this study is to evaluate whether PEG injected into FCVB can serve as a long-term vitreous substitute. In vitro study, a concentration of 5% (w/v) PEG sols showed natural-like mechanical and optical properties in terms of pH, density, light transmittance, refractive index, interfacial tension, viscosity, rheology, and cytotoxicity. Then in vivo tests, 30 rabbits received standard pars plana vitrectomy, of which 12 eyes were implanted with PEG injected into FCVB, nine eyes were injected with PEG sols alone, and nine others were injected with balance salt solution as control. A clinical evaluation of the anterior segment, fundus, and intraocular pressure was measured pre- and postoperatively up to 180 days, which showed that FCVBs had good retina supporting function, except for a higher incidence of cataracts. Gross pathology, hematoxylin and eosin, and terminal deoxynucleotidyl transferase dUTP nick end labeling staining analysis also showed that FCVBs had good biocompatibility, and that all quadrants of the capsular wall fitted well with the retina. This study demonstrated that PEG injected into FCVB can serve as a long-term vitreous substitute and has potential clinical use.

A novel vitreous substitute of using a foldable capsular vitreous body injected with polyvinylalcohol hydrogel.

Hydrogels may be the ideal vitreous substitutes due to their wonderful physical features and biocompatibility. However, their drawbacks, short residence time, and biodegradation in vivo, have led to the fact that none of them have been approved for clinical use. In this study, we developed a novel approach of using a foldable capsular vitreous body (FCVB) injected with polyvinylalcohol (PVA) hydrogel as a vitreous substitute for long-term tamponade. The 3% PVA hydrogel that was cross-linked by gamma irradiation showed good rheological and physical properties and had no toxicity in vitro. After 180 days retention, the 3% PVA hydrogel inside FCVB remained transparent and showed good viscoelasticity without biodegradation and showed good biocompatibility and retina support. This new approach may develop into a valuable tool to improve the stability performance of PVA hydrogel as a vitreous substitute and to extend the application function of FCVB for long-term implantation in vitreous cavity.

Evaluation of the flexibility, efficacy, and safety of a foldable capsular vitreous body in the treatment of severe retinal detachment.

PURPOSE: To determine the flexibility, efficacy, and safety of a novel foldable capsular vitreous body (FCVB) in the treatment of severe retinal detachment in human eyes. METHODS: The study involved 11 patients with 11 severe retinal detachments. A standard three-port pars plana vitrectomy was performed, and the FCVB was triple-folded and implanted into the vitreous cavity. Balanced salt solution was then injected into the capsule of the FCVB to support the retina. The treated eyes were examined by ophthalmoscopy, fundus photography, and tonometry during a 3-month implantation period. B-scan ultrasonography, optical coherence tomography (OCT), ultrasound biomicroscopy (UBM), and electroretinogram (ERG) were also performed. The FCVB was removed and examined in the laboratory at the end of the 3-month treatment time. RESULTS: The FCVB was easily implanted into the vitreous cavity through a 3-mm incision and was easily removed through a 2-mm scleral incision. Retinal reattachment was found in 8 (73%) of 11 eyes at the end of the 3-month treatment time. The fundus, B-scan, and OCT showed that the FCVB was well distributed in the vitreous cavity and evenly supported the retina. IOP and visual acuity in the FCVB-treated eyes did not show a significant difference when compared with the preoperative measurements. UBM showed that the FCVB smoothly contacted but did not crush the ciliary body. Laboratory examinations showed no significant inflammatory cells in the balanced salt solution, no decrease in spectral transmittance, and no blocking of tiny apertures from the FCVB after a 3-month implantation period. CONCLUSIONS: The FCVB was shown to be flexible, effective, and safe as a vitreous substitute over a 3-month implantation time. (ClinicalTrials.gov number, NCT00910702.).

Clinical device-related article evaluation of morphology and functions of a foldable capsular vitreous body in the rabbit eye.

We previously proposed a new strategy to replace a vitreous body with a novel foldable capsular vitreous body (FCVB). In this study, the FCVB was designed to mimic natural vitreous morphology, and evaluate its physiological functions compared with traditional silicone oil substitutes, in an established rabbit model of proliferative vitreoretinopathy. We found that FCVB was a very good replacement for closely mimicking the morphology and restoring the physiological functions, such as the support, refraction, and cellular barriers, of the rabbit vitreous body. The study has provided us with a novel research and therapy strategy that could effectively mimic the morphology and physiological function of the rabbit vitreous body.

Refractive shifts in four selected artificial vitreous substitutes based on Gullstrand-Emsley and Liou-Brennan schematic eyes.

PURPOSE: To determine and compare the refractive shifts based on Gullstrand-Emsley and Liou-Brennan schematic eyes after filling them with four selected artificial vitreous substitutes: silicone oil, heavy silicone oil, hydrogels, and encapsuled balanced salt solution. METHODS: The optical constants of artificial vitreous body-filled eyes were calculated based on Gullstrand-Emsley and Liou-Brennan schematic eyes with accommodation relaxed. The theoretical refractive shifts in these two models were compared in pars plana vitrectomy (PPV), PPV plus lensectomized and PPV plus intraocular lens (IOL) eyes after four artificial vitreous tamponades. RESULTS: The Gullstrand-Emsley schematic eye shows refractive shifts of +8.710, -4.544, +1.136, and -0.338 D in PPV eyes; +11.044, +20.332, +16.351, and +17.413 D in PPV plus lensectomized eyes; and the need for IOL powers of +22.195, +22.366, +22.292, and +22.312 D in PPV plus IOL eyes in silicone oil, heavy silicone oil, hydrogels, and encapsuled balanced salt solution tamponade eyes, respectively. Similarly, the Liou-Brennan schematic eye induced shifts of +6.260, -3.266, +0.817, and -0.272 D in PPV eyes; +13.181, +20.654, +17.451, and +18.305 D in PPV plus lensectomized eyes; and the need IOL powers of +13.522, +23.767, +19.389, and +20.558 D in PPV plus IOL eyes, respectively. CONCLUSIONS: The Gullstrand-Emsley schematic eye is a convenient and accurate model for predicting refractive shifts for hydrogels and encapsuled balanced salt solution substitutes in PPV eyes. The Liou-Brennan schematic eye is recommended for silicone oil and heavy silicone oil in PPV eyes and for all four substitutes in PPV plus lensectomized eyes and PPV plus IOL eyes. In addition, the encapsuled balanced salt solution changes the refraction little in either schematic eye.