Cell Microencapsulation within Gelatin-PEG Microgels Using a Simple Pipet Tip-Based Device.

Microgels are microscale particles of hydrogel that can be laden with cells and used to create macroporous tissue constructs. Their ability to support cell-ECM and cell-cell interactions, along with the high levels of nutrient and metabolite exchange facilitated by their high surface area-to-volume ratio, means that they are attracting increasing attention for a variety of tissue regeneration applications. Here, we present methods for fabricating and modifying the structure of microfluidic devices using commonly available laboratory consumables including pipet tips and PTFE and silicon tubing to produce microgels. Different microfluidic devices realized the controlled generation of a wide size range (130-800 µm) of microgels for cell encapsulation. Subsequently, we describe the process of encapsulating mesenchymal stromal cells in microgels formed by photo-cross-linking of gelatin-norbornene and PEG dithiol. The introduced pipet-based chip offers simplicity, tunability, and versatility, making it easily assembled in most laboratories to effectively produce cell-laden microgels for various applications in tissue engineering.

Multidimensional Analysis of the Mother-to-child Transmission Risk Factors in Chronic Hepatitis B Virus Infection in Pregnant Women in Vietnam.

Background: Hepatitis B virus (HBV) infection remains a major public health problem. The interaction between HBV and the host inflammatory response is an important factor contributing to liver damage and disease development. We investigate of the correlation between peripheral blood cell levels, HBV DNA, and the risk of transmission to the baby in pregnant women infected with hepatitis B. Methods: A multidimensional analysis was performed on data collected from 60 Vietnamese pregnant women and their babies (cord blood). Results: Taking the risk ratio test results of cord blood HBsAg as a positive probability, the boundary of maternal PBMC concentration is 8.03x106 cells/ml (with negative correlation) and for CBMCs is 6.64x106 cells/ml (with positive correlation). That means that HBsAg positivity in the blood may be related to the increasing of CBMCs and the diminution of maternal PBMCs. When the maternal viral load is higher than 5x107 copies/ml, the risk of being HBsAg-positive in cord blood is 123% (RR=2.23 [1.48,3.36]); when the viral load is lower than this baseline, the risk is decreased by 55% (RR=0.45 [0.30,0.67]) (p<0.001). Conclusions: With several steps of the analysis, this study found maternal peripheral blood cell levels and cord blood positively cor-related in pregnant women with a load lower than 5x107 copies of HBV DNA/ml. The study's results suggest that the role of PBMCs and HBV DNA in vertical infection is essential.

Cell-laden injectable microgels: Current status and future prospects for cartilage regeneration.

Injectable hydrogels have been employed extensively as versatile materials for cartilage regeneration due to their excellent biocompatibility, tunable structure, and ability to accommodate bioactive factors, as well as their ability to be locally delivered via minimally invasive injection to fill irregular defects. More recently, in vitro and in vivo studies have revealed that processing these materials to produce cell-laden microgels can enhance cell-cell and cell-matrix interactions and boost nutrient and metabolite exchange. Moreover, these studies have demonstrated gene expression profiles and matrix regeneration that are superior compared to conventional injectable bulk hydrogels. As cell-laden microgels and their application in cartilage repair are moving closer to clinical translation, this review aims to present an overview of the recent developments in this field. Here we focus on the currently used biomaterials and crosslinking strategies, the innovative fabrication techniques being used for the production of microgels, the cell sources used, the signals used for induction of chondrogenic differentiation and the resultant biological responses, and the ability to create three-dimensional, functional cartilage tissues. In addition, this review also covers the current clinical approaches for repairing cartilage as well as specific challenges faced when attempting the regeneration of damaged cartilage tissue. New findings related to the macroporous nature of the structures formed by the assembled microgel building blocks and the novel use of microgels in 3D printing for cartilage tissue engineering are also highlighted. Finally, we outline the challenges and future opportunities for employing cell-laden microgels in clinical applications.

Detection of in vivo hepatitis B virus surface antigen mutations-A comparison of four routine screening assays.

An important requirement for a state-of-the-art hepatitis B surface antigen (HBsAg) screening assay is reliable detection of mutated HBsAg. Currently, there is a striking shortage of data regarding the detection rates of in vivo HBsAg mutations for these clinically important assays. Therefore, we compared the detection rates of four commercial HBsAg screening assays using a global cohort of 1553 patients from four continents with known HBV genotypes. These samples, which represent the broadest spectrum of known and novel HBsAg major hydrophilic region (MHR) mutations to date, were analyzed for the presence of HBsAg using the Roche Elecsys® HBsAg II Qualitative, Siemens ADVIA Centaur XP HBsAg II, Abbott Architect HBsAg Qualitative II and DiaSorin Liaison® HBsAg Qualitative assays, respectively. Of the 1553 samples, 1391 samples could be sequenced; of these, 1013 (72.8%) carried at least one of the 345 currently known amino acid substitutions (distinct HBsAg mutation) in the HBsAg MHR. All 1553 patient samples were positive for HBsAg using the Elecsys® HBsAg II Qual assay, with a sensitivity (95% confidence interval) of 99.94% (99.64%-100%), followed by the Abbott Architect 99.81% (99.44%-99.96%), Siemens ADVIA 99.81% (99.44%-99.96%) and DiaSorin Liaison® 99.36% (98.82%-99.69%) assays, respectively. Our results indicate that the Elecsys® HBsAg II Qual assay exhibits the highest sensitivity among the commercial HBsAg screening assays, and demonstrate that its capacity to detect HBV infection is not compromised by HBsAg MHR mutants.

Treatment of falciparum malaria in Vietnamese children: the need for combination therapy and optimized dosage regimens.

To assess the in vivo sensitivity of Plasmodium falciparum to mefloquine and artesunate in a hyperendemic area of southern Viet Nam, we studied 41 children and 21 adults from a remote commune who had uncomplicated falciparum malaria without previous treatment. Patients were randomly allocated to artesunate (4 mg/kg on day 0 and 2 mg/kg on days 1-4) or mefloquine (10 mg/kg followed by 5 mg/kg at 6 h). Serial assessments were performed over 28 days. Of 31 patients allocated artesunate, nine (29%) redeveloped parasitaemia during follow-up compared with 23% (seven of 30) who received mefloquine. Of the 41 children, 15 (37%) had recrudescence/re-infection compared with only one of 20 adults (5%; p < 0.001). Significantly more children than adults failed on mefloquine treatment (37% vs 0%; p = 0.021) and one case showed RIII resistance. There was no significant difference in the case of artesunate. In regression analysis, parasitaemia was an independent predictor of recrudescence/re-infection after mefloquine (p = 0.02). These data support the use of combination therapy such as artesunate plus mefloquine for falciparum malaria in a hyperendemic area of Viet Nam. Primarily because of their greater parasite densities, children should be given higher doses of mefloquine (e.g. 25 mg/kg).