Chemically Recyclable Biobased Non-Isocyanate Polyurethane Networks from CO2 -Derived Six-membered Cyclic Carbonates.

Non-isocyanate polyurethanes (NIPUs) are widely studied as sustainability potential, because they can be prepared without using toxic isocyanates in the synthesis process. The aminolysis of cyclic carbonate to form NIPUs is a promising route. In this work, a series of NIPUs is prepared from renewable bis(6-membered cyclic carbonates) (iEbcc) and amines. The resulting NIPUs possess excellent mechanical properties and thermal stability. The NIPUs can be remolded via transcarbamoylation reactions, and iEbcc-TAEA-10 (the molar ratio of tris(2-aminoethyl)amine in amines is 10%) still get a recovery ratio of 90% in tensile stress after three cycles of remolding. In addition, the obtained materials can be chemically degraded into bi(1,3-diol) precursors with high purity (>99%) and yield (>90%) through alcoholysis. Meanwhile, the degraded products can be used to regenerate NIPUs with similar structures and properties as the original samples. The synthetic strategy, isocyanate-free and employing isoeugenol and carbon dioxide (CO2 ) as building blocks, makes this approach an attractive pathway to NIPU networks taking a step toward a circular economy.

Biodegradable Ru-Containing Polycarbonate Micelles for Photoinduced Anticancer Multitherapeutic Agent Delivery and Phototherapy Enhancement.

The lack of selectivity between tumor and healthy cells, along with inefficient reactive oxygen species production in solid tumors, are two major impediments to the development of anticancer Ru complexes. The development of photoinduced combination therapy based on biodegradable polymers that can be light activated in the "therapeutic window" would be beneficial for enhancing the therapeutic efficacy of Ru complexes. Herein, a biodegradable Ru-containing polymer (poly(DCARu)) is developed, in which two different therapeutics (the drug and the Ru complex) are rationally integrated and then conjugated to a diblock copolymer (MPEG-b-PMCC) containing hydrophilic poly(ethylene glycol) and cyano-functionalized polycarbonate with good degradability and biocompatibility. The polymer self-assembles into micelles with high drug loading capacity, which can be efficiently internalized into tumor cells. Red light induces the generation of singlet oxygen and the release of anticancer drug-Ru complex conjugates from poly(DCARu) micelles, hence inhibiting tumor cell growth. Furthermore, the phototherapy of polymer micelles demonstrates remarkable inhibition of tumor growth in vivo. Meanwhile, polymer micelles exhibit good biocompatibility with blood and healthy tissues, which opens up opportunities for multitherapeutic agent delivery and enhanced phototherapy.

JNK pathway-associated phosphatase illustrates low expression and negative correlations with inflammation, disease activity, and T-helper 17 cells in inflammatory bowel disease children.

BACKGROUND: C-Jun N-terminal kinase pathway-associated phosphatase (JKAP) modulates the T cell receptor and mitogen-activated protein kinase pathway-mediated autoimmunity, thus participating in the pathogenesis of autoimmune diseases. This study aimed to explore the clinical implication of JKAP in inflammatory bowel disease (IBD) children. METHODS: C-Jun N-terminal kinase pathway-associated phosphatase, tumor necrosis factor-α (TNF-α), interleukin-23, interferon-γ (T-helper 1 secreted cytokine), and interleukin-17A (T-helper 17 secreted cytokine) in serum samples from 140 IBD children (including 60 Crohn's disease (CD) children and 80 ulcerative colitis (UC) children) were detected by ELISA. Meanwhile, JKAP from serum samples of 10 healthy controls (HCs) was also detected by ELISA. RESULTS: C-Jun N-terminal kinase pathway-associated phosphatase was reduced in CD children (median (interquartile range (IQR)): 51.6 (36.8-69.5) pg/ml) and UC children (median (IQR): 57.5 (43.4-78.5) pg/ml) compared with HCs (median (IQR): 101.8 (70.0-143.2) pg/ml) (both p < 0.05). In CD children, JKAP was negatively correlated with C-reactive protein (CRP) (p = 0.016) and erythrocyte sedimentation rate (ESR) (p = 0.029); while in UC children, JKAP was also negatively correlated with CRP (p = 0.006) and ESR (p = 0.022). Regarding the correlation of JKAP with disease activity, it presented negative correlations with PCDAI (p = 0.001) and PUCAI (p = 0.002). Besides, JKAP was negatively related to TNF-α (both p < 0.05) but not interleukin-23 (both p>0.05) in CD and UC children. Additionally, JKAP was not correlated with interferon-γ in CD or UC children (both p>0.05), while negatively correlated with interleukin-17A in CD and UC children (both p < 0.05). CONCLUSION: C-Jun N-terminal kinase pathway-associated phosphatase shows low expression and negative correlations with inflammation, disease activity, and T-helper 17 cells in IBD children.

Study on cooperative constraint zoning of water environment.

This study comprehensively considers two elements of water environmental sensitivity and pressure using the combination of qualitative analysis and quantitative calculation. And it puts forward the water environmental collaborative constraint zoning method and focuses on the construction of the water environmental collaborative constraint zoning evaluation index system using the fuzzy optimization programming model to determine the index weight. This study takes the Liaohe River Basin in Liaoning Province as a study area through two-dimensional quadrant analysis of water environmental sensitivity and pressure; it is divided into four types of areas: high-pressure and high-sensitivity area (HP-HS area), high-pressure and low-sensitivity area (HP-LS area), low-pressure and high-sensitivity area (LP-HS area) and low-pressure and low-sensitivity area (LP-LS area), respectively. The results show that the proportion of HP-HS area is 28.4%, the proportion of HP-LS area is 10.1%, the proportion of LP-HS area is 22.2% and the proportion of LP-LS area is 39.3%, respectively. The evaluation results are in line with the actual situation of the Liaohe River Basin in Liaoning Province. According to the results of different zoning, this research puts forward the optimization and adjustment scheme of industrial layout to achieve the comprehensive and coordinated sustainable development of population, economy, society, and environment in the study area. The research results also have been applied to the formulation of '14th Five-Year Plan' for water ecological environment protection of key river basins in Liaoning Province.

[Long-term follow-up of efficacy of insulin pump in the treatment of children with type 1 diabetes mellitus].

OBJECTIVE: To study the clinical effect of continuous subcutaneous insulin infusion (CSⅡ) versus multiple daily injection (MDI) on blood glucose control in children with type 1 diabetes mellitus (T1DM). METHODS: A retrospective analysis was performed on the medical data of 91 children with T1DM who were treated with CSⅡ for more than 1 year and 75 children with T1DM who were treated with MDI. The two groups were compared in terms of glycosylated hemoglobin (HbA1C) and the recurrence of diabetic ketoacidosis (DKA) to evaluate the difference in the efficacy during the 3-year follow-up. A survey was conducted for the children in the CSⅡ group and their family members to investigate the degree of satisfaction with insulin pump. RESULTS: There was no significant difference in age, sex, and course of diabetes between the CSⅡ and MDI groups at disease onset and in the first year, the second year, and the third year of follow-up (P > 0.05). There was no significant difference in the HbA1C level between the two groups at disease onset (P > 0.05), but in the first year of follow-up, the CSⅡ group had a significantly lower HbA1C level than the MDI group (P=0.04). There was no significant difference in the HbA1C level between the two groups in the second year and the third year of follow-up (P > 0.05). The CSⅡ group had a higher proportion of children with HbA1C < 7.5% than the MDI group in the first year, the second year, and the third year of follow-up (P > 0.05). Within the 3 years of follow-up, 2 children in the CSⅡ group and 8 in the MDI group experienced the recurrence of DKA. In the third year of follow-up, there was no significant difference in blood pressure and blood lipids between the CSⅡ and MDI groups (P > 0.05). Most children and their family members (87%) were satisfied with CSⅡ treatment. CONCLUSIONS: Children with T1DM treated with CSⅡ have a better control of blood glucose than those treated with MDI, and children and their family members are satisfied with CSⅡ treatment. Therefore, it holds promise for clinical application.

End-Chain Fluorescent Highly Branched Poly(l-lactide)s: Synthesis, Architecture-Dependence, and Fluorescent Visible Paclitaxel-Loaded Microspheres.

A facile method in combination of "grafting from" and "end-functionalization" was developed for the synthesis of fluorescent highly branched poly(l-lactide)s (PLLA-COU) via ring opening polymerization (ROP) and esterification end-capping. These resulting PLLA-COU with four kinds of architectures, including linear, star, linear-comb, and star-comb structures, were subjected to characterization and application as fluorescent visible paclitaxel-loaded microspheres. The mutual effects of architecture and end-groups on thermal and fluorescence properties, enzymatic degradation, and drug release behaviors were focused. Contrast to linear and star PLLA-COU, two comb-shaped analogues demonstrated higher fluorescence quantum yield, faster drug release, and lower enzymatic degradation rate. All the fluorescent microspheres could maintain fluorescence traceability. The fluorescent PLLA-COU displayed negligible toxicity and good biocompatibility. This work highlights that the fluorescent highly branched poly(l-lactide)s are properties-tailored and used as fluorescent visible drug delivery systems (DDS) for potential theranostic applications.

Mechanically Robust and Chemically Recyclable Polyhydroxyurethanes from CO2-Derived Six-Membered Cyclic Carbonates.

In the current context of sustainable chemistry development and new regulations, aminolysis of cyclic carbonate is one of the most promising routes to nonisocyanate polyurethanes, also called polyhydroxyurethanes (PHU). In this study, a new kind of shape memory PHU vitrimers with outstanding mechanical properties and chemical recyclability is prepared. The monomer employed for aminolysis to form the PHUs is bis(six-membered cyclic carbonate) of 4,4'-biphenol (BCC-BP), which is synthesized by bi(1,3-diol) precursors and CO2. The synthetic strategy, isocyanate-free and employing CO2 as a building block, is environmentally friendly and suits the concept of carbon neutrality. The thermal properties, mechanical properties, and dynamic behaviors of the PHUs are explored. The maximum breaking strength and elongation at break of the resultant PHUs reach 65 MPa and 452%, respectively, exceeding other reported PHU-based materials in combined performance. Such a PHU material can also lift up a load 4700 times heavier than its own weight by a shape recovery process. Finally, the bi(1,3-diol) can be regenerated through the alcoholysis of PHUs to realize chemical recycling. This work provides a feasibility study for a green synthetic approach and for designing a novel PHU material with outstanding properties.

Cost-effectiveness analysis of continuous subcutaneous insulin infusion versus multiple daily insulin for treatment of children with type 1 diabetes.

OBJECTIVE: To evaluate the health economics of using continuous subcutaneous insulin infusion (CSII) therapy versus multiple daily injections (MDI) therapy in children and adolescent patients with type 1 diabetes (T1D) in Qingdao, China. METHODS: A long-term cost-effectiveness analysis was conducted using the IQVIA Core Diabetes Model (CDM). The baseline characteristics of the simulated cohorts were obtained from 213 pediatric T1D patients who received care with CSII(104 cases) or MDI(109 cases) in Qingdao from 1 January 2015 to 31 March 2019. In the essential case, the expenditure of the complications and treatment of the disease with both therapies were evaluated in Chinese currency from the perspective of healthcare system. In a secondary analysis, the model used a 70-year time horizon, and a discount rate of 5% was applied to all future health outcomes and costs. A one-way sensitivity analysis was conducted on delta HbA1c, different prices of insulin pump, price of each upgrade cycle rates and different discount rates. Uncertainty was also evaluated by the probability sensitivity analysis and scenario analysis. RESULTS: In the base-case analysis, the lifetime total costs were lower for CSII group at ¥630,871 per patient compared with ¥672,672 for MDI group. The quality-adjusted life years (QALYs) gained were 11.612 and 11.197 for patients treated with CSII group and MDI group, respectively. The CSII group was cost-saving compared to MDI group. The feasibility of CSII group being cost-effective was 100% under the threshold of 3 times per capita GDP of China in 2019 (¥212,676) which was indicated from the probabilistic sensitivity analysis. Regarding scenario analysis, the ICER of the CSII group compared to MDI was between -151,583 and 153,366 RMB/QALYs, which is cost-effective. CONCLUSIONS: This economic evaluation compared CSII therapy versus MDI therapy for T1D children and adolescent patients in China and findings indicate that CSII should be considered a preferred treatment modality to MDI.

Case report: genetic analysis of a child with 18q deletion syndrome and developmental dysplasia of the hip.

OBJECTIVE: To analyze the genotypes and phenotypes of a child with developmental dysplasia of the hip (DDH), developmental delays, recurrent fever, hypothyroidism and cleft palate. METHODS: G-banding karyotyping analysis and next-generation sequencing (NGS) were performed for the patient. The genotypes of the parents of the patient were verified by copy number variation analysis and Sanger sequencing to determine the source of variations. RESULTS: The karyotype of the patient was 46, XX. A 10.44 Mb deletion (chr18:67562936-78005270del) at 18q22.2q23 was found by NGS. We identified 2 HSPG2 mutations (chr1: 22206699, c.2244C > A, exon 17, p.H748Q; chr1: 22157321-22157321, c.11671 + 154insA, intron). One mutation was inherited from the father, and the other was inherited from the mother. CONCLUSION: This is the first 18q deletion syndrome case accompanied by DDH. Most phenotypes of this patient, such as developmental delays and cleft palate, may be related to the 18q22.2q23 deletion, but no variants in genes related to DDH were found in this deletion region. DDH may be related to mutations of HSPG2.

Clinical Outcome and Cost-Effectiveness Analysis of CSII Versus MDI in Children and Adolescent With Type 1 Diabetes Mellitus in a Public Health Care System of China.

Objectives: To evaluate the clinical and economic consequences of continuous subcutaneous insulin infusion (CSII) vs. multiple daily injections (MDI) in children and adolescents with type 1 diabetes mellitus (T1DM) from a public health care system in developed areas of developing country, considering changes in glycemic Control, daily insulin requirements, lipid profile, body mass index (BMI), frequency of severe hypoglycemia and Diabetic Ketoacidosis (DKA) and diabetic complications. Methods: This was a retrospective cohort study of children and adolescents with T1DM. Data were collected at baseline and the end of every year including glycated hemoglobin (HbA1c), insulin dose, lipid profile, blood pressure, and adverse events (severe hypoglycemia and DKA). The Cost-effectiveness analysis was performed using the IQVIA CORE Diabetes Model (CDM) to simulate diabetes progression by utilizing the clinical data obtained from the two groups. The main outcome measures were Life Expectancy, Quality adjusted life years (QALYs), Total Costs and Incremental Costs and Effectiveness Ratio (ICER) of CSII compared with MDI in Chinese pediatric patients with T1DM in Qingdao City (60 years). Results: Mean HbA1c values and daily insulin doses were significantly lower in those receiving CSII therapy throughout follow-up. Mean direct lifetime costs were ¥ 67,137 higher with CSII treatment than with MDI for pediatric patients. Treatment with CSII was associated with an improvement in life expectancy of 0.41 years for pediatric patients compared with MDI based on CORE diabetes model simulation. The corresponding gains in QALYs were 0.42. These data produced corresponding ICER is ¥ 161,815 per QALY for pediatric T1DM patients in Qingdao. Sensitivity analyses suggested that our base-case assumptions were mostly robust. Conclusions: CSII is associated with improved long-term clinical outcomes compared with MDI. Based on this model analysis, CSII appears to be more cost-effective for the Qingdao TIDM pediatric population and health care system.

A Sequential Dual-Model Strategy Based on Photoactivatable Metallopolymer for On-Demand Release of Photosensitizers and Anticancer Drugs.

The synergistic combination of chemotherapy and photodynamic therapy has attracted considerable attention for its enhanced antitumoral effects; however, it remains challenging to successfully delivery photosensitizers and anticancer drugs while minimizing drug leakage at off-target sites. A red-light-activatable metallopolymer, Poly(Ru/PTX), is synthesized for combined chemo-photodynamic therapy. The polymer has a biodegradable backbone that contains a photosensitizer Ru complex and the anticancer drug paclitaxel (PTX) via a singlet oxygen (1 O2 ) cleavable linker. The polymer self-assembles into nanoparticles, which can efficiently accumulate at the tumor sites during blood circulation. The distribution of the therapeutic agents is synchronized because the Ru complex and PTX are covalently conjugate to the polymer, and off-target toxicity during circulation is also mostly avoided. Red light irradiation at the tumor directly cleaves the Ru complex and produces 1 O2 for photodynamic therapy. Sequentially, the generated 1 O2 triggers the breakage of the linker to release the PTX for chemotherapy. Therefore, this novel sequential dual-model release strategy creates a synergistic chemo-photodynamic therapy while minimizing drug leakage. This study offers a new platform to develop smart delivery systems for the on-demand release of therapeutic agents in vivo.

Agarose droplet microfluidics for highly parallel and efficient single molecule emulsion PCR.

An agarose droplet method was developed for highly parallel and efficient single molecule emulsion PCR. The method capitalizes on the unique thermoresponsive sol-gel switching property of agarose for highly efficient DNA amplification and amplicon trapping. Uniform agarose solution droplets generated via a microfluidic chip serve as robust and inert nanolitre PCR reactors for single copy DNA molecule amplification. After PCR, agarose droplets are gelated to form agarose beads, trapping all amplicons in each reactor to maintain the monoclonality of each droplet. This method does not require cocapsulation of primer labeled microbeads, allows high throughput generation of uniform droplets and enables high PCR efficiency, making it a promising platform for many single copy genetic studies.

Gonadal dysgenesis in Turner syndrome with Y-chromosome mosaicism: Two case reports.

BACKGROUND: Turner syndrome (TS) has a variety of different karyotypes, with a wide range of phenotypic features, but the specific karyotype may not always predict the phenotype. TS with Y chromosome mosaicism may have mixed gonadal dysgenesis, and the mosaicism is related to the potential for gonadoblastoma. CASE SUMMARY: In this case report, we report two cases of TS with different karyotypes and gonadal dysgenesis. Patient 1 had obvious virilization, and was positive for the SRY gene, but her karyotype in peripheral blood lymphocytes was 45X. Patient 2 had a mosaic karyotype, 45X/46X, dic (Y:Y) (p11.3:p11.2), and the proportion of Y-bearing cells was 50% in peripheral blood lymphocytes, but the patient had normal female external genitalia and streaky gonads, with no genital virilism. Different tissues in the same TS individual may exhibit different ratios of mosaicism. The gonadal determination and differentiation of mosaic TS are primarily dependent on the predominant cell line in the gonads. CONCLUSION: In TS patients with virilization, it is necessary to test at least two to three tissues to search for cryptic Y material.

Hydrolytic Degradation of Comb-Like Graft Poly (Lactide-co-Trimethylene Carbonate): The Role of Comonomer Compositions and Sequences.

The effect of sequence on copolymer properties is rarely studied, especially the degradation behavior of the biomaterials. A series of linear-comb block, gradient, random copolymers were successfully achieved using hydroxylated polybutadiene as the macroinitiator by simple ring-opening polymerization of l-lactide (l-LA) and 1,3-trimethylene carbonate (TMC). The hydrolytic degradation behaviors of the copolymers were systemically evaluated by using nuclear magnetic resonance (NMR), gel permeation chromatography (GPC), differential scanning calorimeter (DSC), and scanning electron microscopy (SEM) to illustrate the influences of comonomer compositions and sequence structures. The linear-comb block copolymers (lcP(TMC-b-LLA)) with different compositions had different degradation rates, which increased with l-LA content. Thermal property changes were observed with decreased Tm and increased ΔHm in all block copolymers during the degradation. To combine different sequence structures, unique degradation behaviors were observed for the linear-comb block, gradient and random copolymers even with similar comonomer composition. The degradation rates of linear-comb PLLA-gradient-PTMC (lcP(LLA-grad-TMC)) and linear-comb PLLA-random-PTMC (lcP(LLA-ran-TMC)) were accelerated due to the loss of regularity and crystallinity, resulting in a remarkable decrease on weight retention and molar mass. The hydrolysis degradation rate increased in the order lcP(TMC-b-LLA), lcP(LLA-ran-TMC), lcP(LLA-grad-TMC). Therefore, the hydrolytic degradation behavior of comb-like graft copolymers depends on both the compositions and the sequences dramatically.

Synthesis, microstructure and mechanical properties of partially biobased biodegradable poly(ethylene brassylate-co-ε-caprolactone) copolyesters.

High-molecular-weight poly(ethylene brassylate-co-ε-caprolactone) copolyesters within a wide composition range were prepared via triphenyl bismuth catalyzed copolymerization of ethylene brassylate (EB) and ε-caprolactone (ε-CL) in bulk. Microstructural analysis of the resulting copolyesters demonstrated that the comonomer units were completely random distribution. DSC and WAXD recognized that the copolyesters cocrystallize within the lattices analogous to either of the parent homopolymers. It confirmed the isodimorphism behavior with a pseudo-eutectic point of melting temperatures as well as lattice spacings at 75 mol% ε-CL units. The crystal cell would be stretched in one dimension rather than expanding in both dimensions with the incorporation of comonomer units according to the result of WAXD. The mechanical properties of the copolyesters are well tunable by the composition, and its trend is consistent with the isodimorphism behavior, in particular, the maximum elongation at break over 2000% is located at the pseudo-eutectic point. The intralamellar shear occurred at the low tensile rate while both intralamellar shear and interlamellar shear occurred at high tensile rate. The copolymers exhibit excellent hydrolytic stability.

Development of biodegradable polyesters based on a hydroxylated coumarin initiator towards fluorescent visible paclitaxel-loaded microspheres.

In this work, we developed a facile end-functionalization method using hydroxylated coumarin to initiate the ring-opening polymerization of cyclic esters to synthesize a series of fluorescent biodegradable aliphatic polyesters with tailorable properties. The resulting fluorescent functionalized poly(l-lactide) (PLLA-COU), poly(ε-caprolactone) (PCL-COU) poly(δ-valerolactone) (PVL-COU) and poly(trimethylene carbonate) (PTMC-COU) were investigated to evaluate the dependence of fluorescence on the chemical structure and molecular weight of the materials. The differences in the electron withdrawing ability and the density of ester groups are responsible for the changes in the fluorescence quantum yield. Then, two representative biodegradable materials, namely, PLLA-COU and PCL-COU, were used to prepare fluorescent paclitaxel-loaded microspheres. During in vitro drug release, the release rate of the PCL-COU microspheres is dramatically faster than that of the PLLA-COU microspheres due to the difference in the material nature and their surface morphologies, possibly achieving a tunable degradation and release rate for the drug carriers. Fluorescent functionalized polyester microspheres can retain their fluorescence properties and emit bright blue light for fluorescence tracing during the degradation process. Biological evaluations showed that both fluorescent polyesters are devoid of any significant toxicity and have good biocompatibility. The results demonstrated that the obtained fluorescent polyesters are promising for use in traceable and controlled drug delivery with tunable drug release.

Relationships between Architectures and Properties of Highly Branched Polymers: The Cases of Amorphous Poly(trimethylene carbonate) and Crystalline Poly(ε-caprolactone).

Highly branched polymers (HBPs) are a special class of functional polymeric materials and possess unique properties due to their unique topological structure. A new series of highly branched linear-comb and star-comb amorphous poly(trimethylene carbonate)s (PTMC) and crystalline poly(ε-caprolactone)s (PCL) with well-defined structure and high molecular weight were first synthesized using hydroxylated polybutadiene (HPB) as macroinitiators by simple "one-step" and "graft from" strategies. It is expected that the impact of long-chain, highly branched architecture on the properties of amorphous and crystalline polymers, respectively, is different. We explored systematically for the first time the effect and comparison of branched architectures on the physical and chemical properties of highly branched PTMCs and PCLs, including the intrinsic viscosity, glass transition, thermal degradation, creep property, rheological property, and crystallization and melting behaviors. It is found that the intrinsic viscosities in solution for both comb-branched PTMCs and PCLs were much lower compared with their linear and star counterparts arise from more compact structure and smaller hydrodynamic volumes. For amorphous PTMC, the creep strain and rate increased remarkably with degree of branching increasing due to the shorter side chains making it difficult for the highly branched molecules to entangle. For crystalline PCL, both WAXD and DSC analysis of PCLs with different topological structures indicated that the comb branched architectures have no significant influence on the crystal structure of PCL, but greatly promote the crystallization behavior, e.g., higher crystallinities. The deep understanding of structure-property relationship expects to guide the synthesis of designed functional polymer materials and the processing of polymer products.

Agarose droplet microfluidics for highly parallel and efficient single molecule emulsion PCR.

Agarose emulsion droplet microfluidic technology for single copy emulsion PCR (ePCR) is a suitable technique for the detection of single copy DNA molecules. It improves the traditional ePCR by employing agarose with low melting and low gelling temperatures, which is coupled with PCR forward primers using Schiff-base reaction. Highly uniform monodisperse nanoliter agarose droplets each containing PCR reagents and single copy template are produced with a microfabricated emulsion generator. Following PCR, the cooled droplets transform to microbeads carrying amplicons to maintain the monocolonity of each droplet, which can be further analyzed. This method allows high-throughput generation of uniform droplets and enables high PCR efficiency, making it a promising platform for many single copy genetic studies.

Highly sensitive and quantitative detection of rare pathogens through agarose droplet microfluidic emulsion PCR at the single-cell level.

Genetic alternations can serve as highly specific biomarkers to distinguish fatal bacteria or cancer cells from their normal counterparts. However, these mutations normally exist in very rare amount in the presence of a large excess of non-mutated analogs. Taking the notorious pathogen E. coli O157:H7 as the target analyte, we have developed an agarose droplet-based microfluidic ePCR method for highly sensitive, specific and quantitative detection of rare pathogens in the high background of normal bacteria. Massively parallel singleplex and multiplex PCR at the single-cell level in agarose droplets have been successfully established. Moreover, we challenged the system with rare pathogen detection and realized the sensitive and quantitative analysis of a single E. coli O157:H7 cell in the high background of 100,000 excess normal K12 cells. For the first time, we demonstrated rare pathogen detection through agarose droplet microfluidic ePCR. Such a multiplex single-cell agarose droplet amplification method enables ultra-high throughput and multi-parameter genetic analysis of large population of cells at the single-cell level to uncover the stochastic variations in biological systems.