Molecular recognition reagents are key tools for understanding biological processes and are used universally by scientists to study protein expression, localisation and interactions. Antibodies remain the most widely used of such reagents and many show excellent performance, although some are poorly characterised or have stability or batch variability issues, supporting the use of alternative binding proteins as complementary reagents for many applications. Here we report on the use of Affimer proteins as research reagents. We selected 12 diverse molecular targets for Affimer selection to exemplify their use in common molecular and cellular applications including the (a) selection against various target molecules; (b) modulation of protein function in vitro and in vivo; (c) labelling of tumour antigens in mouse models; and (d) use in affinity fluorescence and super-resolution microscopy. This work shows that Affimer proteins, as is the case for other alternative binding scaffolds, represent complementary affinity reagents to antibodies for various molecular and cell biology applications.

Kidney transplants from young paediatric donors are uncommonly performed in the UK. Published literature of kidney transplant from donors under 5kg in weight is sparse. We present our initial experience of en bloc kidney transplantation (EKT) from donors under 20kg in weight including neonatal donors. All recipients undergoing EKT from donors under 20kg at our centre from January 2005 to October 2016 were included. Donor and recipient details were recorded from a prospective database. Electronic patient records were examined for follow‐up data. Of 30 EKT included, 15 were from ≤5kg donors and 15 from >5kg donors (median weight 3.4kg and 12.7kg, respectively). 1‐year graft survival for ≤5kg and >5kg donor EKT was 86.7% and 93.3% (p=0.85), respectively. Progressive improvement in eGFR was noted in both donor categories through first year post‐transplant but in the ≤5kg donor category, significant improvement was seen at 12 months compared to 3 months post‐transplant (median eGFR 37.3 vs 70.0ml/min/1.73m², p=0.03). Two early graft losses were attributable to early vascular complications and one graft loss due to primary non‐function. Our data shows that kidney transplantation from such donors is a feasible option at centres with experience of EKT albeit with increased risk of early graft loss.

Mouse models of human diseases are an essential part of the translational pipeline. Orthotopic tumour mouse models are increasingly being used in cancer research due to their increased clinical relevance over subcutaneous xenograft models, particularly in relation to metastatic disease. In this study, we have developed orthotopic colorectal cancer liver metastases (CRCLM) and primary cholangiocarcinoma (CCA) models in BALB/c nude mice using minimally invasive ultrasound-guided intrahepatic injection. Due to its minimally invasive nature, the method reduced risk from surgical complications whilst being fast and easy to perform and resulted in measurable tumour volumes 1 to 3 weeks post-injection. Tumour volumes were monitored in vivo by weekly high-frequency ultrasound (HF-US) and/or twice weekly bioluminescence imaging (BLI) and confirmed with end-point histology. Take rates were high for human CRC cells (>73%) and for CCA cells (90%). We have demonstrated that this method reliably induces CRCLM and CCAs, in which tumour volume can be monitored throughout using HF-US and/or BLI. This provides a promising experimental tool for future testing of cancer therapeutics in an orthotopic model.