Clinical efficacy of tumor organoid-guided cancer therapy for locally advanced unresectable or metastatic breast cancer.

Patient-derived organoids (PDOs) may facilitate treatment selection. This retrospective cohort study evaluated the feasibility and clinical benefit of using PDOs to guide personalized treatment in metastatic breast cancer (MBC). Patients diagnosed with MBC were recruited between January 2019 and August 2022. PDOs were established and the efficacy of customized drug panels was determined by measuring cell mortality after drug exposure. Patients receiving organoid-guided treatment (OGT) were matched 1:2 by nearest neighbor propensity scores with patients receiving treatment of physician's choice (TPC). The primary outcome was progression-free survival. Secondary outcomes included objective response rate and disease control rate. Targeted gene sequencing and pathway enrichment analysis were performed. Forty-six PDOs (46 of 51, 90.2%) were generated from 45 MBC patients. PDO drug screening showed an accuracy of 78.4% (95% CI 64.9%-91.9%) in predicting clinical responses. Thirty-six OGT patients were matched to 69 TPC patients. OGT was associated with prolonged median progression-free survival (11.0 months vs. 5.0 months; hazard ratio 0.53 [95% CI 0.33-0.85]; p = .01) and improved disease control (88.9% vs. 63.8%; odd ratio 4.26 [1.44-18.62]) compared with TPC. The objective response rate of both groups was similar. Pathway enrichment analysis in hormone receptor-positive, human epidermal growth factor receptor 2-negative patients demonstrated differentially modulated pathways implicated in DNA repair and transcriptional regulation in those with reduced response to capecitabine/gemcitabine, and pathways associated with cell cycle regulation in those with reduced response to palbociclib. Our study shows that PDO-based functional precision medicine is a feasible and effective strategy for MBC treatment optimization and customization.

A non-invasive artificial intelligence model for identifying axillary pathological complete response to neoadjuvant chemotherapy in breast cancer: a secondary analysis to multicenter clinical trial.

BACKGROUND: This study aims to develop a stacking model for accurately predicting axillary lymph node (ALN) response to neoadjuvant chemotherapy (NAC) using longitudinal MRI in breast cancer. METHODS: We included patients with node-positive breast cancer who received NAC following surgery from January 2012 to June 2022. We collected MRIs before and after NAC, and extracted radiomics features from the tumour, peritumour, and ALN regions. The Mann-Whitney U test, least absolute shrinkage and selection operator, and Boruta algorithm were used to select features. We utilised machine learning techniques to develop three single-modality models and a stacking model for predicting ALN response to NAC. RESULTS: This study consisted of a training cohort (n = 277), three external validation cohorts (n = 313, 164, and 318), and a prospective cohort (n = 81). Among the 1153 patients, 60.62% achieved ypN0. The stacking model achieved excellent AUCs of 0.926, 0.874, and 0.862 in the training, external validation, and prospective cohort, respectively. It also showed lower false-negative rates (FNRs) compared to radiologists, with rates of 14.40%, 20.85%, and 18.18% (radiologists: 40.80%, 50.49%, and 63.64%) in three cohorts. Additionally, there was a significant difference in disease-free survival between high-risk and low-risk groups (p < 0.05). CONCLUSIONS: The stacking model can accurately predict ALN status after NAC in breast cancer, showing a lower false-negative rate than radiologists. TRIAL REGISTRATION NUMBER: The clinical trial numbers were NCT03154749 and NCT04858529.

Noninvasive Artificial Intelligence System for Early Predicting Residual Cancer Burden during Neoadjuvant Chemotherapy in Breast Cancer.

OBJECTIVE: To develop an artificial intelligence (AI) system for the early prediction of residual cancer burden (RCB) scores during neoadjuvant chemotherapy (NAC) in breast cancer. SUMMARY BACKGROUND DATA: RCB III indicates drug resistance in breast cancer, and early detection methods are lacking. METHODS: This study enrolled 1048 patients with breast cancer from four institutions, who were all receiving NAC. Magnetic resonance images were collected at the pre- and mid-NAC stages, and radiomics and deep learning features were extracted. A multitask AI system was developed to classify patients into three groups (RCB 0-I, II, and III ) in the primary cohort (PC, n=335). Feature selection was conducted using the Mann-Whitney U- test, Spearman analysis, least absolute shrinkage and selection operator regression, and the Boruta algorithm. Single-modality models were developed followed by model integration. The AI system was validated in three external validation cohorts. (EVCs, n=713). RESULTS: Among the patients, 442 (42.18%) were RCB 0-I, 462 (44.08%) were RCB II and 144 (13.74%) were RCB III. Model-I achieved an area under the curve (AUC) of 0.975 in the PC and 0.923 in the EVCs for differentiating RCB III from RCB 0-II. Model-II distinguished RCB 0-I from RCB II-III, with an AUC of 0.976 in the PC and 0.910 in the EVCs. Subgroup analysis confirmed that the AI system was consistent across different clinical T stages and molecular subtypes. CONCLUSIONS: The multitask AI system offers a noninvasive tool for the early prediction of RCB scores in breast cancer, supporting clinical decision-making during NAC.

[Value of functional echocardiographic parameters in predicting refractory septic shock in neonates]. / åŠŸèƒ½æ€§è¶ å£°å¿ƒåŠ¨å›¾å‚æ•°åœ¨æ–°ç”Ÿå„¿è„“æ¯’ç—‡ä¼‘å ‹ä¸­çš„ä¸´åºŠåº”ç”¨ä»·å€¼.

OBJECTIVES: To study the value of functional echocardiographic parameters in predicting refractory septic shock in neonates. METHODS: A total of 72 neonates with septic shock were enrolled. According to the highest value of septic shock score, they were divided into two groups: refractory (n=30) and non-refractory (n=42). The two groups were compared in terms of clinical data, laboratory findings, and functional echocardiographic parameters. The receiver operating characteristic (ROC) curve was used to evaluate the performance of functional echocardiographic parameters in predicting refractory septic shock. RESULTS: Compared with the non-refractory group, the refractory group had significantly lower cardiac output and cardiac index (CI) and a significantly higher mean arterial pressure (MAP)/CI ratio (P<0.05). CI had a cut-off value of 2.6 L/(min·m2), a sensitivity of 79%, a specificity of 83%, and an area under the ROC curve (AUC) of 0.841 in predicting septic shock-related death (P<0.05), and MAP/CI ratio had a cut-off value of 11.4, a sensitivity of 83%, a specificity of 73%, and an AUC of 0.769 (P<0.05). CI had a cut-off value of 2.9 L/(min·m2), a sensitivity of 69%, a specificity of 69%, and an AUC of 0.717 in predicting all-cause death within 28 days (P<0.05). CONCLUSIONS: CI and MAP/CI ratio can be useful for early prediction of septic shock-related death in neonates.

BRD4 and PIN1 gene polymorphisms are associated with high pulse pressure risk in a southeastern Chinese population.

BACKGROUND: BRD4 and PIN1 have been described to be involved in inflammation and vascular endothelial cell dysfunction, which in turn may increase pulse pressure. HYPOTHESIS: Genetic mutations within the BRD4 and PIN1 genes could affect the risk of high pulse pressure. METHODS: A total of four single nucleotide polymorphisms (SNPs) (BRD4: rs4808278; PIN1: rs2233678, rs2287838, and rs2233682) were genotyped in a cohort of 666 hypertensive patients and 232 normotensive controls with Chinese Han origin. Generalized multifactor dimensionality reduction (GMDR) was used to screen the best interaction combination among the four SNPs within the BRD4 and PIN1 genes and diabetes. Logistic regression analysis was performed to calculate the odds ratio (ORs) (95% confidence interval (CI)) for the association between the four SNPs. RESULTS: Adjusted for age, weight, waist circumference, drinking, smoking, hypertension, and diabetes, high pulse pressure risk was significantly higher for carriers with the rs4808278-TT genotype in BRD4 than those with wild genotypes (OR: 0.400, 95% CI: 0.217-0.737, P* < 0.05). However, we did not find any significant association of rs2233678, rs2287838, and rs2233682 in PIN1 with high pulse pressure susceptibility after covariate adjustment. GMDR analysis indicated a significant three-locus model (P = 0.0107) involving rs4808278, rs2233678, and diabetes, the cross-validation consistency of the three-locus models was 9/10, and the testing accuracy was 57.47%. CONCLUSIONS: Genetic mutations within BRD4 (rs4808278) could affect the susceptibility to high pulse pressure in a southeastern Chinese population.

Effects of Storage Time and Temperature on Antioxidants in Juice from Momordica charantia L. and Momordica charantia L. var. abbreviata Ser.

This study determined the antioxidant activities of juice from Momordica charantia L. (MC) and MC var. abbreviata Ser. (MCVAS) by analyzing 1,1-diphenyl-2-picrylhydrazyl (DPPH) scavenging ability, ferric reducing power (FRP), and total phenolic content (TPC). The effects of storage time and storage temperature on these antioxidant activities were investigated. Liquid chromatography-mass spectrometry was conducted to identify the major components of MC and MCVAS. The results revealed that the antioxidant activity of MCVAS was better than that of MC, possibly because of richer components of MCVAS. For MC and MCVAS, the scavenging concentrations of 50% DPPH were 3.33 and 1.19 mg/mL, respectively; moreover, the FRP values were 68.93 and 118.14 mg ascorbic acid equivalent/g dry weight, respectively; and the TPC values were 8.15 and 11.47 mg gallic acid equivalent/g dry weight, respectively. The antioxidant activities of MC and MCVAS decreased with storage time. High storage temperature decreased antioxidant activity more quickly than a low temperature. In addition, MC had exhibited a faster decline in DPPH scavenging ability and FRP than MCVAS during 24-day storage, but no difference was observed in TPC.

Gibberellic acid targeting ZBTB16 reduces NF-κB dependent inflammatory stress in sepsis-induced neuroinflammation.

OBJECTIVE: Sepsis is frequently complicated by neuroinflammation. Gibberellic acid (GA3) is recognized for its anti-inflammatory properties. In this study, our objective was to investigate whether GA3 could alleviate Nuclear factor-kappa B (NF-κB) -dependent inflammatory stress in sepsis-induced neuroinflammation. METHODS: C57BL/6 J mice were administered 10 mg/kg lipopolysaccharide (LPS) to induce sepsis. BV2 cells were pre-incubated with GA3 and subjected lipopolysaccharide stimulation to replicate the inflammatory microglia during sepsis. Subsequently, we assessed the release of IL-6, TNF-α, and IL-1ß, along with the expression of Zbtb16, NF-κB, and IκB. To investigate whether any observed anti-inflammatory effects of GA3 were mediated through a Zbtb16-dependent mechanism, Zbtb16 was silenced using siRNA. RESULTS: GA3 improved the survival of sepsis mice and alleviated post-sepsis cognitive impairment. Additionally, GA3 attenuated microglial M1 activation (pro-inflammatory phenotype), inflammation, and neuronal damage in the brain. Moreover, GA3 inhibited the release of TNF-α, IL-6, and IL-1ß in microglia stimulated with LPS. The NF-κB signaling pathway emerged as one of the key molecular pathways associated with the impact of GA3 on LPS-stimulated microglia. Lastly, GA3 upregulated Zbtb16 expression in microglia that had been downregulated by LPS. The inhibitory effects of GA3 on microglial M1 activation were partially reversed through siRNA knockdown of Zbtb16. CONCLUSIONS: Pre-incubation of microglia with GA3 led to the upregulation of the NF-κB regulator, Zbtb16. This process counteracted LPS-induced microglial M1 activation, resulting in an anti-inflammatory effect upon subsequent LPS stimulation.

Synthesis of water-dispersible zinc oxide quantum dots with antibacterial activity and low cytotoxicity for cell labeling.

Typical photoluminescent semiconductor nanoparticles, called quantum dots (QDs), have potential applications in biological labeling. When used to label stem cells, QDs may impair the differentiation capacity of the stem cells. In this study, we synthesized zinc oxide (ZnO) QDs in methanol with an average size of ∼2 nm. We then employed two different types of polyethylene glycol (PEG) molecules (SH-PEG-NH2 and NH2-PEG-NH2) to conjugate ZnO QDs and made them water-dispersible. Fourier transform infrared spectroscopy spectra indicated the attachment of PEG molecules on ZnO QDs. No obvious size alteration was observed for ZnO QDs after PEG conjugation. The water-dispersible ZnO QDs still retained the antibacterial activity and fluorescence intensity. The cytotoxicity evaluation revealed that ZnO QDs at higher concentrations decreased cell viability but were generally safe at 30 ppm or below. Cell lines of hepatocytes (HepG2), osteoblasts (MC3T3-E1) and mesenchymal stem cells (MSCs) were successfully labeled by the water-dispersible ZnO QDs at 30 ppm. The ZnO QD-labeled MSCs maintained their stemness and differentiation capacity. Therefore, we conclude that the water-dispersible ZnO QDs developed in this study have antibacterial activity, low cytotoxicity, and proper labeling efficiency, and can be used to label a variety of cells including stem cells.

Multifactor artificial intelligence model assists axillary lymph node surgery in breast cancer after neoadjuvant chemotherapy: multicenter retrospective cohort study.

BACKGROUND: The high false negative rate (FNR) associated with sentinel lymph node biopsy often leads to unnecessary axillary lymph node dissection following neoadjuvant chemotherapy (NAC) in breast cancer. The authors aimed to develop a multifactor artificial intelligence (AI) model to aid in axillary lymph node surgery. MATERIALS AND METHODS: A total of 1038 patients were enrolled, comprising 234 patients in the primary cohort, 723 patients in three external validation cohorts, and 81 patients in the prospective cohort. For predicting axillary lymph node response to NAC, robust longitudinal radiomics features were extracted from pre-NAC and post-NAC magnetic resonance images. The U test, the least absolute shrinkage and selection operator, and the spearman analysis were used to select the most significant features. A machine learning stacking model was constructed to detect ALN metastasis after NAC. By integrating the significant predictors, we developed a multifactor AI-assisted surgery pipeline and compared its performance and false negative rate with that of sentinel lymph node biopsy alone. RESULTS: The machine learning stacking model achieved excellent performance in detecting ALN metastasis, with an area under the curve (AUC) of 0.958 in the primary cohort, 0.881 in the external validation cohorts, and 0.882 in the prospective cohort. Furthermore, the introduction of AI-assisted surgery reduced the FNRs from 14.88 (18/121) to 4.13% (5/121) in the primary cohort, from 16.55 (49/296) to 4.05% (12/296) in the external validation cohorts, and from 13.64 (3/22) to 4.55% (1/22) in the prospective cohort. Notably, when more than two SLNs were removed, the FNRs further decreased to 2.78% (2/72) in the primary cohort, 2.38% (4/168) in the external validation cohorts, and 0% (0/15) in the prospective cohort. CONCLUSION: Our study highlights the potential of AI-assisted surgery as a valuable tool for evaluating ALN response to NAC, leading to a reduction in unnecessary axillary lymph node dissection procedures.

Homologous recombination deficiency predicts the response to platinum-based neoadjuvant chemotherapy in early-stage triple-negative breast cancer patients: a systematic review and meta-analysis.

Background: Recent studies have shown that homologous recombination deficiency (HRD) may be correlated with the pathological complete response (pCR) rate. This meta-analysis aimed to determine the predictive value of HRD for the pCR rate in patients with triple-negative breast cancer (TNBC) receiving platinum-based neoadjuvant chemotherapy (NCT). Methods: Published articles were searched in the PubMed, Embase, Medline, Web of Science, and Cochrane databases up to 1 June 2021, and studies reporting the pCR rate for HRD carriers on platinum-based NCT were selected. Odds ratios (ORs) with 95% confidence intervals (CIs) were determined for the pCR rate, clinical response rate, and Grade 3 or higher adverse events (AEs) using the random-effects model. Bias risk was evaluated using the Cochrane Collaboration tool (PROSPERO, registration number CRD42021249874). Results: Seven studies were eligible. The results showed that HRD carriers had higher pCR rates than non-HRD carriers across all treatment arms (OR = 3.84, 95% CI = [1.93, 7.64], p = 0.0001). Among HRD carriers, the pCR rate was higher in patients on platinum-based NCT than in those without platinum exposure (OR = 1.95, 95% CI = [1.17, 3.23], p = 0.01). We did not observe marked pCR improvements in non-HRD carriers. Among HRD carriers, the pCR rates in the mutant and wild-type breast cancer susceptibility gene (BRCA) groups did not differ significantly (OR = 2.00, 95% CI = [0.77, 5.23], p = 0.16), but HRD carriers with wild-type BRCA had a significant advantage over non-HRD carriers on platinum-based NCT (OR = 3.64, 95% CI = [1.83, 7.21], p = 0.0002). Conclusion: HRD is an effective predictor of increased pCR rates in platinum-based NCT, especially in wild-type BRCA patients. Adding platinum to NCT for non-HRD carriers can increase the incidence of AEs but may not improve the therapeutic effect.

Cell-derived artificial nanovesicle as a drug delivery system for malignant melanoma treatment.

Extracellular vehicles have a natural targeting ability and immune tolerance of being usually applied in drug delivery systems; however, the purification of EVs is complicated and the production yield was quite low. We developed an artificial cellular mimetic nanovesicle (NV) with melanoma fragment membrane for the transportation with curcumin to achieve the anticancer purpose. B16F10 derived NVs were manufactured by the breakdown of cells using a series of extrusions through cut-off size filters (10 and 5 µm), and the whole procedure was easy and time-saving. To terminate the suspicion of cancer metastatic issue, B16F10 cells were treated by 30-min sonication and 1-min UVB exposure to remove genetic materials before the extrusion. B16F10 derived NV loaded with curcumin was called NV(S30U1/Cur), and the anticancer effect was evaluated by cell-based viability, immune, migration, and invasion. The results showed that NVs were manufactured by passing through 10 and 5 µm filters having an enviable production yield, and the mRNA amounts were declined within NVs produced by B16F10 cells treated with UVB in a comparison to the control group. NV(S30U1/Cur) were effectively decreased B1610 cell viability, and migratory and invasive abilities were also reduced significantly. Besides, CD8+ expression of murine primary lymphocytes was activated with CD4+ reduction by NV(S30U1/Cur) to stimulate the inherent tumor suppressive capacity in the immune system. Taken together, we established bioengineered NVs serving as novel cell mimetic nanocarriers to deliver natural compound for malignant melanoma potential immune chemotherapy. DATA AVAILABILITY STATEMENT: The data used to support the findings of this study are available from the corresponding author upon requests.

Neoadjuvant therapy in triple-negative breast cancer: A systematic review and network meta-analysis.

BACKGROUND: Evidence for the preferred neoadjuvant therapy regimen in triple-negative breast cancer (TNBC) is not yet established. METHODS: Literature search was conducted from inception to February 12, 2022. Phase 2 and 3 randomized controlled trials (RCTs) investigating neoadjuvant therapy for TNBC were eligible. The primary outcome was pathologic complete response (pCR); the secondary outcomes were all-cause treatment discontinuation, disease-free survival or event-free survival (DFS/EFS), and overall survival. Odd ratios (OR) with 95% credible intervals (CrI) were used to estimate binary outcomes; hazard ratios (HR) with 95% CrI were used to estimate time-to-event outcomes. Bayesian network meta-analysis was implemented for each endpoint. Sensitivity analysis and network meta-regression were done. RESULTS: 41 RCTs (N = 7109 TNBC patients) were eligible. Compared with anthracycline- and taxane-based chemotherapy (ChT), PD-1 inhibitor plus platinum plus anthracycline- and taxane-based ChT was associated with a significant increased pCR rate (OR 3.95; 95% CrI 1.81-9.44) and a higher risk of premature treatment discontinuation (3.25; 1.26-8.29). Compared with dose-dense anthracycline- and taxane-based ChT, the combined treatment was not associated with significantly improved pCR (OR 2.57; 95% CrI 0.69-9.92). In terms of time-to-event outcomes, PD-1 inhibitor plus platinum plus anthracycline- and taxane-based ChT was associated with significantly improved DFS/EFS (HR 0.42; 95% CrI 0.19-0.81). CONCLUSIONS: PD-1 inhibitor plus platinum and anthracycline- and taxane-based ChT was currently the most efficacious regimen for pCR and DFS/EFS improvement in TNBC. The choice of chemotherapy backbone, optimization of patient selection with close follow-up and proactive symptomatic managements are essential to the antitumor activity of PD-1 inhibitor.

Focused ion beam-fabricated Au micro/nanostructures used as a surface enhanced Raman scattering-active substrate for trace detection of molecules and influenza virus.

The focused ion beam (FIB) technique was used to precisely fabricate patterned Au micro/nanostructures (fibAu). The effects of surface enhanced Raman scattering (SERS) on the fibAu samples were investigated by adjusting the geometrical, dimensional, and spacing factors. The SERS mechanism was evaluated using low-concentration rhodamine 6G (R6G) molecules, physically adsorbed or suspended on/within the micro/nanostructures. The results indicated that for detecting R6G molecules, hexagon-like micro/nanostructures induced a higher electromagnetic mechanism (EM) due to the availability of multiple edges and small curvature. By decreasing the dimensions from 300 to 150 nm, the laser-focused area contained an increasing number of micro/nanostructures and therefore intensified the excitation of SERS signals. Moreover, with an optimized geometry and dimensions of the micro/nanostructures, the relative intensity/surface area value reached a maximum as the spacing was 22 nm. An exponential decrease was found as the spacing was increased, which most probably resulted from the loss of EM. The spacing between the micro/nanostructures upon the fibAu was consequently regarded as the dominant factor for the detection of R6G molecules. By taking an optimized fibAu to detect low-concentration influenza virus, the amino acids from the outermost surface of the virus can be well distinguished through the SERS mechanism.

A Novel Biocompatible Herbal Extract-Loaded Hydrogel for Acne Treatment and Repair.

A novel herbal extract-loaded gel containing several biofunctional extracts, including green tea, Zingiber officinale Rosc, Phyllanthus emblica, and salicylic acid, was developed for acne vulgaris. These natural raw materials were blended with suitable dosages of gelatin and carboxymethyl cellulose (CMC) to produce a biocompatible herbal gel. The physical chemistry properties of the hydrogel were determined by Fourier transform infrared spectroscopy (FTIR), thermal gravimetric analysis (TGA), rheometry, and scanning electron microscopy (SEM), and the hydrogel showed good mechanical and morphological characteristics. The herbal extract-loaded hydrogel mimicked extracellular matrix properties and showed good antioxidant and anti-inflammatory properties and various advantages, serving as a potential wound dressing material because of its high moisture retention ability, wound exudate absorption behavior, and biocompatibility. It exhibited moderate-high antioxidative and anti-inflammatory qualities that were important for dermis wound closure. The clinical trial results showed that most patients experienced moderate to high healing rates, and four of twenty-four individuals (16.67%) had recovery area ratios greater than 80%. This herbal extract-loaded hydrogel has effective ingredients and excellent mechanical properties as a bioactive dressing agent for acne treatment.

Adjuvant CDK4/6 inhibitors combined with endocrine therapy in HR-positive, HER2-negative early breast cancer: A meta-analysis of randomized clinical trials.

BACKGROUND: The benefit of adjuvant cyclin-dependent kinase 4 and 6 (CDK4/6) inhibitors with endocrine therapy (ET) in hormone receptor-positive, human epidermal growth factor 2 receptor-negative (HR+/HER2-) early breast cancer (EBC) is uncertain. Hence, we performed a meta-analysis to determine the efficacy and safety of adjuvant CDK4/6 inhibitors plus ET and to identify potential preferred subpopulations for this regimen. METHODS: A literature search was conducted in PubMed, Embase, Cochrane databases up to Jan 15, 2021. Hazard ratios (HRs) for invasive disease-free survival (IDFS) and risk ratios (RRs) for grade 3/4 adverse events (AEs) and treatment discontinuation were extracted. Analysis with predefined subgroup variables was done. Trial sequential analysis (TSA) was performed to assess the conclusiveness of survival outcomes. RESULTS: Three trials were eligible (N = 12647). Compared with ET, adjuvant CDK4/6 inhibitors with ET prolonged IDFS in patients with HR+/HER2- EBC (HR 0.87, 95% CI 0.76-0.98, p = 0.03, I2 = 19%), with positive therapeutic responses observed in patients with N2/N3 nodal status (HR 0.83, 95% CI 0.71-0.97, p = 0.02, I2 = 0%). None of the cumulative z-curves crossed the trial monitoring boundaries in TSA, and no reliable conclusion could be drawn. The combination treatment carried a higher risk of grade 3/4 AEs (RR 4.14, 95% CI 3.33-5.15, p < 0.00001) and an increase in treatment discontinuation due to AEs (RR 19.16, 95% CI 9.27-39.61, p < 0.00001). CONCLUSIONS: Adjuvant CDK4/6 inhibitors with ET might provide survival benefit in HR+/HER2- EBC. A statistically significantly improved IDFS was only observed in N2/N3 subgroup. However, overall evidence favoring the use of this combination regimen was inadequate.

Probed adhesion force of living lung cells with a tip-modified atomic force microscope.

The mechanical properties of the extracellular matrix play an important role in bio-microenvironment activities. Herein, atomic force microscope (AFM) was used to measure the interaction between Au and Ag nanoparticle (NP) clusters on the surface of human fetal lung cells. Using (3-mercapto-propyl) triethoxysilane (MPTMS), NP clusters were grafted onto the apex of AFM tip, and then, the adhesion force between the tip and the cell was analyzed. The measured adhesion force increased from 92 pN for AFM tip to 332 pN for that modified with MPTMS. The increase is most probably contributed by the nonspecific interactions between the apex of the modified AFM tip and the surface of the cells. The adhesion forces between the surface of NPs clusters grafted AFM tip and that of lung cells were dramatically reduced as NPs clusters were replaced by MPTMS. For the former, as the Au NPs cluster was applied, the adhesion force reached to 122 pN, whereas it significantly augmented with the addition of the cluster's size and dimension on the AFM tip. For the case of Ag cluster grafted on AFM tip, its adhesion force with the surface of the cells significantly lowered and reduced to 56 pN. Presumably, the electrostatic or van der Waals force between the two surfaces results in the variation of measurements. It is also very likely that the cell-surface interactions are probably varied by the nature of the contact surfaces, like the force-distance of attraction. The result is significant for understanding the the nature of the interactions between the surface of NPs and the membrane of lung cells.

Stability of biodegradable waterborne polyurethane films in buffered saline solutions.

The stability of polyurethane (PU) is of critical importance for applications such as in coating industry or as biomaterials. To eliminate the environmental concerns on the synthesis of PU which involves the use of organic solvents, the aqueous-based or waterborne PU (WBPU) has been developed. WBPU, however, may be unstable in an electrolyte-rich environment. In this study, the authors reported the stability of biodegradable WBPU in the buffered saline solutions evaluated by atomic force microscopy (AFM). Various biodegradable WBPU films were prepared by spin coating on coverslip glass, with a thickness of ∼300 nm. The surface AFM images of poly(ε-caprolactone) (PCL) diol-based WBPU revealed nanoglobular structure. The same feature was observed when 20% molar of the PCL diol soft segment was replaced by polyethylene butylenes adipate diol. After hydration in buffered saline solutions for 24 h, the surface domains generally increased in sizes and became irregular in shape. On the other hand, when the soft segment was replaced by 20% poly(l-lactide) diol, a meshlike surface structure was demonstrated by AFM. When the latter WBPU was hydrated, the surface domains appeared to be disconnected. Results from the attenuated total reflectance infrared spectroscopy and x-ray photoelectron spectroscopy indicated that the surface chemistry of WBPU films was altered after hydration. These changes were probably associated with the neutralization of carboxylate by ions in the saline solutions, resulting in the rearrangements of soft and hard segments and causing instability of the WBPU.

Water-based synthesis and processing of novel biodegradable elastomers for medical applications.

Biodegradable elastomers in the form of polyurethane nanoparticles (NPs) were successfully synthesized based on the combinations of two hydrolysis-prone polyester diols by a green water-based process. The anionic nature of the polymers successfully rendered polyurethane NPs (30-50 nm) consisting of approximately 200-300 polymer chains. The mechanical properties and degradation rate could be adjusted by the types and ratios of the component oligodiols in the soft segment. We demonstrated the feasibility using these biodegradable NPs as building blocks to generate self-assembled morphologies in nanometric, micrometric, or bulk scale, bearing excellent elasticity and biocompatibility. The elastic NPs and their various assembled forms represent a series of smart biodegradable elastomers with potential medical applications.

Target-size embracing dimension for sensitive detection of viruses with various sizes and influenza virus strains.

The focused ion beam (FIB) technique was employed to precisely fabricate hexagon-like Au nano-rods (fibAu_h) arrays as a surface enhanced Raman scattering - active substrate. A "ring diameter" (D(R)) was created by the convergence of three fibAu_h with respect to the dimension of the target viruses (D(T)), such as adenovirus (Adeno), encephalomyocarditis virus (EMCV), influenza virus (H1N1) with different sizes. Three influenza A virus strains were also compared. The results indicate that as that with a D(R)/D(T) ratio of around 1, the discrimination ability for detecting the target viruses and SERS mechanism become obvious. The enhanced lightning rod effect surrounding the seized target virus is anticipated if its size and dimension is suitably embraced within three fibAu_h. Hence the as-designed fibAu_h sample with a target-size embracing dimension provides good discrimination ability for distinguishing virus of various sizes or virus strains.