Bridging the Gap between Digital Assays and Point-of-Care Testing: Automated, Low Cost, and Ultrasensitive Detection of Thyroid Stimulating Hormone.

Medical diagnostics is moving toward disease-related target detection at very low concentrations because of the (1) quest for early-stage diagnosis, at a point where only limited target amounts are present, (2) trend toward minimally invasive sample extraction, yielding samples containing low concentrations of target, and (3) need for straightforward sample collection, usually resulting in limited volume collected. Hence, diagnostic tools allowing ultrasensitive target detection at the point-of-care (POC) are crucial for simplified and timely diagnosis of many illnesses. Therefore, we developed an innovative, fully integrated, semi-automated, and economically viable platform based on (1) digital microfluidics (DMF), enabling automated manipulation and analysis of very low sample volumes and (2) low-cost disposable DMF chips with microwell arrays, fabricated via roll-to-roll processes and allowing digital target counting. Thyroid stimulating hormone detection was chosen as a relevant application to show the potential of the system. The assay buffer was selected using design of experiments, and the assay was optimized in terms of reagent concentration and incubation time toward maximum sensitivity. The hydrophobic-in-hydrophobic microwells showed an unparalleled seeding efficiency of 97.6% ± 0.6%. A calculated LOD of 0.0013 µIU/mL was obtained, showing the great potential of the platform, especially taking into account the very low sample volume analyzed (1.1 µL). Although validation (in biological matrix) and industrialization (full automation) steps still need to be taken, it is clear that the combination of DMF, low-cost DMF chips, and digital analyte counting in microwell arrays enables the implementation of ultrasensitive and reliable target detection at the POC.

Prevalence of wound complications following Mohs micrographic surgery (MMS): a cross-sectional study of 1000 patients undergoing MMS and wound repair in a UK teaching hospital.

BACKGROUND: Mohs micrographic surgery (MMS) for nonmelanoma skin cancer is often quoted as having an excellent safety profile. AIM: To determine the complication rate of patients undergoing MMS in a large UK Mohs unit and subdivide complication rates into mild/intermediate and major, and to identify potential risk factors necessitating a clinical intervention. METHODS: This was a single-centre, cross-sectional study of 1000 consecutive cases of MMS performed with in-house repair. Notes from the postsurgical dressing clinics were reviewed at Visit 1 (Days 7-14) and Visit 2 (approximately Week 6). Based upon the intervention required and effect on cosmetic/functional outcome, complications were classified as minor, intermediate or major. Logistic regression modelling was used to identify risk factors associated with a complication that needed a clinical intervention (i.e. intermediate or major). RESULTS: In total, 1000 Mohs surgeries were performed on 803 patients, resulting in 1067 excisions. Complication rates in our cohort were low (minor 3.6%, intermediate 3.1% and major 0.8%) Potential risk factors for developing a complication included skin graft (unadjusted OR = 4.89, 95% CI 1.93-12.39; fully adjusted OR = 7.13, 95% CI 2.26-22.45) and patients undergoing surgery on the forehead (unadjusted OR = 3.32, 95% CI 0.95-11.58; fully adjusted OR = 5.34, 95% CI 1.40-20.42). Patients whose wounds were allowed to heal by secondary intention healing (6.8%) exhibited no complications. CONCLUSION: We advocate that patients should be informed during the consent procedure that less than 1 in every 100 patients (0.75%) undergoing MMS will have a serious adverse event (major complication) affecting their cosmetic or functional outcome.

Photodynamic Therapy for Basal Cell Carcinoma: The Clinical Context for Future Research Priorities.

Photodynamic therapy (PDT) is an established treatment option for low-risk basal cell carcinoma (BCC). BCC is the most common human cancer and also a convenient cancer in which to study PDT treatment. This review clarifies challenges to researchers evident from the clinical use of PDT in BCC treatment. It outlines the context of PDT and how PDT treatments for BCC have been developed hitherto. The sections examine the development of systemic and subsequently topical photosensitizers, light delivery regimens, and the use of PDT in different patient populations and subtypes of BCC. The outcomes of topical PDT are discussed in comparison with alternative treatments, and topical PDT applications in combination and adjuvant therapy are considered. The intention is to summarize the clinical relevance and expose areas of research need in the BCC context, ultimately to facilitate improvements in PDT treatment.

Digital enzyme-linked immunosorbent assays with sub-attomolar detection limits based on low numbers of capture beads combined with high efficiency bead analysis.

We report the development of digital enzyme-linked immunosorbent assays (ELISAs) based on single molecule arrays (Simoa) with improved sensitivities over conventional digital ELISA, enabling detection of proteins at sub-attomolar concentrations. The improvements in sensitivity were based on using fewer beads to capture the target proteins (≤5000 vs.∼500 000 beads) that increased the ratio of molecules to beads, and increasing the fraction of beads that were analyzed (bead read efficiency) from ∼5% to ∼50%. Bead read efficiency was increased by: a) improving the loading of beads into arrays of microwells by combining capillary and magnetic forces in a method called magnetic-meniscus sweeping (MMS); b) using a centrifugal washer to minimize bead loss during the assay; and, c) improved optics and image analysis to enable the analysis of more microwells. Using this approach, we developed an assay for IL-17A with a limit of detection (LOD) of 0.7 aM, 437-fold more sensitive than standard digital ELISA. A digital ELISA with improved sensitivity was used to measure IL-17A in 100 serum and plasma samples with 100% detectability, compared to 51% for standard digital ELISA. Low numbers of capture beads yielded improved LODs for IL-12p70 (0.092 aM), p24 (9.1 aM), and interferon alpha (45.9 aM). IL-4 and PSA showed no improvements in sensitivity using fewer beads, primarily due to low antibody loading on beads and increased non-specific binding, respectively. The results were consistent with a kinetic model of binding that showed that combining capture antibodies with high on-rates with high antibodies per bead yields the greatest improvement in sensitivity.

Genetic silencing of striatal CaV1.3 prevents and ameliorates levodopa dyskinesia.

BACKGROUND: Levodopa-induced dyskinesias are an often debilitating side effect of levodopa therapy in Parkinson's disease. Although up to 90% of individuals with PD develop this side effect, uniformly effective and well-tolerated antidyskinetic treatment remains a significant unmet need. The pathognomonic loss of striatal dopamine in PD results in dysregulation and disinhibition of striatal CaV1.3 calcium channels, leading to synaptopathology that appears to be involved in levodopa-induced dyskinesias. Although there are clinically available drugs that can inhibit CaV1.3 channels, they are not adequately potent and have only partial and transient impact on levodopa-induced dyskinesias. METHODS: To provide unequivocal target validation, free of pharmacological limitations, we developed a CaV1.3 shRNA to provide high-potency, target-selective, mRNA-level silencing of striatal CaV1.3 channels and examined its ability to impact levodopa-induced dyskinesias in severely parkinsonian rats. RESULTS: We demonstrate that vector-mediated silencing of striatal CaV1.3 expression in severely parkinsonian rats prior to the introduction of levodopa can uniformly and completely prevent induction of levodopa-induced dyskinesias, and this antidyskinetic benefit persists long term and with high-dose levodopa. In addition, this approach is capable of ameliorating preexisting severe levodopa-induced dyskinesias. Importantly, motoric responses to low-dose levodopa remained intact in the presence of striatal CaV1.3 silencing, indicating preservation of levodopa benefit without dyskinesia liability. DISCUSSION: The current data provide some of the most profound antidyskinetic benefit reported to date and suggest that genetic silencing of striatal CaV1.3 channels has the potential to transform treatment of individuals with PD by allowing maintenance of motor benefit of levodopa in the absence of the debilitating levodopa-induced dyskinesia side effect. © 2019 The Authors. Movement Disorders published by Wiley Periodicals, Inc. on behalf of International Parkinson and Movement Disorder Society.

The safety and efficacy of sonidegib for the treatment of locally advanced basal cell carcinoma.

INTRODUCTION: Basal cell carcinomas (BCCs) are the commonest malignancy in the Western world. Locally advanced BCCs (laBCCs) represent tumours that have developed in difficult-to-treat facial sites, aggressively recurrent tumours, large neglected tumours and those in which current treatment options are excluded by clinical or patient-driven criteria. It is estimated laBCCs represent 1% of BCCs. AREAS COVERED: Sonidegib is an oral hedgehog pathway inhibitor with a novel structure. It has recently been licensed for the treatment of laBCC. This article provides a comprehensive review of the literature regarding sonidegib, detailing the pharmacology of the compound, clinical trial data, competitor compounds and a future perspective. Expert commentary: Sonidegib is a novel smoothened (SMO) inhibitor with comparable efficacy to vismodegib, with patient response rates of 44% (sonidegib) and 43% (vismodegib). The adverse effect profile of these two treatments is similar with the main effects being considered to be class effects of SMO inhibitors.