Synthesis and Characterizations of New Lysine-Based Biodegradable Cationic Poly(urethane-co-ester) and Study on Self-Assembled Nanoparticles with DNA

Single-cell transcriptomic analysis of honeybee brains identifies vitellogenin as caste differentiation-related factor

The honeybee (Apis mellifera) is a well-known eusocial insect. In honeybee colonies, thousands of sterile workers, including nurse and forager bees, perform various tasks within or outside the hive, respectively. The queen is the only fertile female and is responsible for reproduction. The queen and workers share similar genomes but occupy different caste statuses. We established single-cell transcriptomic atlases of brains from queens and worker subcastes and identified five major cell groups: Kenyon, optic lobe, olfactory projection, glial, and hemocyte cells. By dividing Kenyon and glial cells into multiple subtypes based on credible markers, we observed that vitellogenin (vg) was highly expressed in specific glial-cell subtypes in brains of queens. Knockdown of vg at the early larval stage significantly suppressed the development into adult queens. We demonstrate vg expression as a "molecular signature" for the queen caste and suggest involvement of vg in regulating caste differentiation.

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scRNA-seq revealed distinct gene expression in the brains of queens and workers

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Vitellogenin (vg) may represent a "molecular signature" of the queen caste

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Knockdown of vg at early larval stage suppressed development into adult queens

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Vg may be involved in regulating caste differentiation

Tailor-made compostable polyurethanes

Designed polyurethanes with degradable ester units all throughout the polymer backbone and quaternized ammonium units in the hard segment (tensile strength ∼30 MPa, elongation at break ∼1400%) show degradation in 35 days in industrial compost.

Bioreducible poly(urethane amine)s for robust nucleic acid transfection in stem cells

The search for cationic polymeric carriers enabling robust gene transfection against stem cells remains a challenge. Herein, linear bioreducible poly(urethane amine)s (denoted as SSPUAs) with repeated disulfide and protonable amino groups were prepared and used as non-viral vectors for in vitro gene transfection of different stem cells. The polyurethane copolymers (denoted as SSBT) with varied molar ratios of 1,4-bis(3-aminopropyl)piperazine (BAP) and tris(2-aminoethyl) amine (TAA) moieties could lead to superb transfection activity against human adipose-derived stem cells (hADSCs) and human bone marrow stem cells (hBMSCs). Data indicated that under optimal transfection conditions, SSBT10 with a BAP/TAA molar ratio of 90/10 caused the transfection of ∼60% of green fluorescence protein-positive (GFP⁺) hADSCs, and SSBT30 with the ratio of 70/30 resulted in the transfection of ∼40% of GFP⁺ hBMSCs. Also, the SSBT30 and polyurethane with BAP residues (denoted as SSBAP) could mediate efficient gene transfer into bone marrow stem cells of experimental animals such as SD rats, beagle dogs and rhesus monkeys, with ∼40-70% of GFP⁺ cells. Additionally, the SSBAP elicited robust transfection ability (∼60% of GFP⁺ cells) against E14 mouse embryonic stem cells without compromising the expression of multipotent stemness-related markers of the cells. Importantly, the transfection efficiencies of these SSPUAs were higher as compared to those yielded by 25 kDa branched polyethylenimine and Lipofectamine 2000 reagents as positive controls. The SSBT30 was further practical to deliver siRNAs into hADSCs for BCL2L2 or TRIB2 gene silencing, causing superior gene silencing efficacy to Lipofectamine 2000. Besides their high gene transfection or silencing efficacy, these SSPUAs revealed low cytotoxicity against stem cells. This study highlights the SSPUA system as a distinct platform for robust nucleic acid delivery into stem cells.

Lysine-derived, pH-sensitive and biodegradable poly(beta-aminoester urethane) networks and their local drug delivery behaviour

In this study, a series of covalently crosslinked, l-lysine based poly(beta-aminoester urethane) (LPBAEU) networks with good biodegradability and pH sensitivity was reported. The effect of hydrophilic/hydrophobic characteristics and diacrylate/amine molar ratio on the structure, swelling and degradation behaviour of the networks was investigated. The water transport mechanism and dynamic swelling behavior of the LPBAEU networks were strongly affected by medium pH, and swelling amounts up to 252.2% and 148.7% were observed at pH 5.6 and pH 7.4, respectively. It was found that water diffusion within the networks followed a non-Fickian mechanism. The LPBAEU network with the highest diacrylate/amine molar ratio exhibited the highest tensile strength and Young's modulus. In vitro mass losses of networks showed that the degradation rate of LPBAEU networks can be adjusted from 4 to 14 days. LPBAEU networks also supported loading of doxycycline hyclate (DH) and in vitro release studies demonstrated that release of DH from the networks was substantially hindered in the neutral pH environment, with 20.9-56.2% DH release, whereas DH release was accelerated under mild acidic conditions, with a release percentage of 36.6-99.6%. The release data were fitted to different mathematical models and the obtained results confirmed that these networks released DH in a non-Fickian mechanism. The results of this research support the idea that pH-responsive LPBAEU networks may find potential applications in local drug delivery.

Advances in Waterborne Polyurethane-Based Biomaterials for Biomedical Applications

Polyurethane (PU) is one of the most popular synthetic elastomers and widely employed in biomedical fields owing to the excellent biocompatibility and hemocompatibility known today. In addition, PU is simply prepared and its mechanical properties such as durability, elasticity, elastomer-like character, fatigue resistance, compliance or tolerance in the body during the healing, can be mediated by modifying the chemical structure. Furthermore, modification of bulk and surface by incorporating biomolecules such as anticoagulant s or biorecognizable groups, or hydrophilic/hydrophobic balance is possible through altering chemical groups for PU structure. Such modifications have been designed to improve the acceptance of implant. For these reason, conventional solventborne (solvent-based) PUs have established the standard for high performance systems, and extensively used in medical devices such as dressings, tubing, antibacterial membrane , catheters to total artificial heart and blood contacting materials, etc. However, waterborne polyurethane (WPU) has been developed to improve the process of dissolving PU materials using toxic organic solvents, in which water is used as a dispersing solvent. The prepared WPU materials have many advantages, briefly (1) zero or very low levels of organic solvents, namely environmental-friendly (2) non-toxic, due to absence of isocyanate residues, and (3) good applicability caused by extensive structure/property diversity as well as an environment-friendly fabrication method resulting in increasing applicability. Therefore, WPUs are being in the spotlight as biomaterials used for biomedical applications . The purpose of this review is to introduce an environmental- friendly synthesis of WPU and consider the manufacturing process and application of WPU and/or WPU based nanocomposites as the viewpoint of biomaterials.

Synthesis and characterization of cationic glycidyl-based poly(aminoester)-folic acid targeting conjugates and study on gene delivery

A new poly(aminoester) (EPAE-FA) containing folic acid and amino groups in the backbone and side chain was synthesized. EPAE-FA self-assembled readily with the plasmid DNA (pCMV-βgal) in HEPES buffer and was characterized by dynamic light scattering, zeta potential, fluorescence images, and XTT cell viability assays. To evaluate the transfection effect of graft ratio of FA on the EPAE system, EPAE-FA polymers with two different graft ratios (EPAE-FA12k and EPAE-FA14k) were also prepared. This study found that all EPAE-FA polymers were able to bind plasmid DNA and yielded positively charged complexes with nano-sized particles (<200 nm). To assess the transfection efficiency mediated by EPAE and EPAE-FA polymers, we performed in vitro transfection activity assays using FR-negative (COS-7) and FR-positive (HeLa) cells. The EPAE-FA12k/DNA and EPAE-FA14k/DNA complexes were able to transfect HeLa cell in vitro with higher transfection efficiency than PEI25k/DNA at the similar weight ratio. These results demonstrated that the introduction of FA into EPAE system had a significant effect on transferring ability for FR-positive cells (HeLa). Examination of the cytotoxicity of PEI25k and EPAE-FA system revealed that EPAE-FA system had lower cytotoxicity. In this paper, EPAE-FA seemed to be a novel cationic poly(aminoester) for gene delivery and an interesting candidate for further study.