ABSTRACT
Fast and simultaneous forward and reverse blood grouping has long remained elusive. Forward blood grouping detects antigens on red blood cells, whereas reverse grouping identifies specific antibodies present in plasma. We developed a paper-based assay using immobilized antibodies and bromocresol green dye for rapid and reliable blood grouping, where dye-assisted color changes corresponding to distinct blood components provide a visual readout. ABO antigens and five major Rhesus antigens could be detected within 30 s, and simultaneous forward and reverse ABO blood grouping using small volumes (100 µl) of whole blood was achieved within 2 min through on-chip plasma separation without centrifugation. A machine-learning method was developed to classify the spectral plots corresponding to dye-based color changes, which enabled reproducible automatic grouping. Using optimized operating parameters, the dye-assisted paper assay exhibited comparable accuracy and reproducibility to the classical gel-card assays in grouping 3550 human blood samples. When translated to the assembly line and low-cost manufacturing, the proposed approach may be developed into a cost-effective and robust universal blood-grouping platform.
Subject(s)
Blood Grouping and Crossmatching/methods , Coloring Agents/chemistry , Paper , Point-of-Care Systems , Feasibility Studies , Fluorescein/chemistry , Humans , Indicators and Reagents , Reproducibility of Results , SpectrophotometryABSTRACT
BACKGROUND: Surgical excision (SE) is a first-line treatment for basal cell carcinoma (BCC). Topical photodynamic therapy (PDT) has also been used and has cosmetic advantages over surgery. The latest European guidelines for topical PDT recommended that it be used to treat nodular basal cell carcinoma (nBCC) but a consensus has not been reached. Our study was to evaluate the efficacy of PDT versus SE for the treatment for nBCC by a meta-analysis. MATERIALS AND METHODS: We searched PubMed, EMBASE, the Cochrane Library, CKNI, VIP, and relevant references up to October 2014 including randomized controlled trials (RCTs) that compared PDT with SE for treatment of nBCC patients. A meta-analysis was conducted by using the Cochrane Collaboration's revman 5.0 software. RESULTS: We selected five studies that covered 596 of pathologically confirmed nBCC. We compared complete response rate (RR) of PDT and SE at 3 months and 1, 2, 3, 4, and 5 years. We found that the RR was 0.95 (0.90, 1.00), 0.89 (0.80, 0.99), 0.83 (0.69, 1.00), 0.73 (0.63, 0.85), 0.84 (0.65, 1.08), and 0.79 (0.61, 1.03), respectively, for those time points, the cumulative probability of recurrence for the time points post-treatment, with an estimate at RR 5.28 (1.85, 15.12), 6.48 (2.46, 17.09), 9.67 (3.02, 30.99), 7.73 (2.81, 21.28), and 8.25 (3.01-22.62), respectively. CONCLUSION: We observed no significant differences between PDT and SE for the complete RR, but there was an increased cumulative probability of recurrence. More large-scale RCTs are required to verify our findings.
