Direct-write printing of stem cells within biomaterials presents an opportunity to engineer tissue for in vitro modeling and regenerative medicine. Here, a first example of constructing neural tissue by printing human neural stem cells that are differentiated in situ to functional neurons and supporting neuroglia is reported. The supporting biomaterial incorporates a novel clinically relevant polysaccharide-based bioink comprising alginate, carboxymethyl-chitosan, and agarose. The printed bioink rapidly gels by stable cross-linking to form a porous 3D scaffold encapsulating stem cells for in situ expansion and differentiation. Differentiated neurons form synaptic contacts, establish networks, are spontaneously active, show a bicuculline-induced increased calcium response, and are predominantly gamma-aminobutyric acid expressing. The 3D tissues will facilitate investigation of human neural development, function, and disease, and may be adaptable for engineering other 3D tissues from different stem cell types.

Dear Editor, The novel coronavirus (CoV) disease termed COVID-19 (coronavirus disease-19) caused by SARS-CoV-2 (severe acute respiratory syndrome coronavirus-2) 1 is causing a massive pandemic worldwide, threatening public health systems across the globe. During this ongoing COVID-19 outbreak, nucleic-acid detection has played an important role in early diagnosis 2. To date, four protocols based on CRISPR for detecting SARS-CoV-2 have been published 3-6. Using lateral flow protocols, RNA samples harboring more than 1 × 10 4-1 × 10 5 copies/mL (SHERLOCK) or 1 × 10 4 copies/mL (DETECTR) can be detected within 1 hour. In addition to these reported efforts, we have also established a SARS-CoV-2 detection protocol based on our previously reported platform-CDetection (Cas12bmediated DNA detection) 7. By combining sample treatment protocols and nucleic-acid amplification methods with CDetection, we have established an integrated viral nucleic-acid detection platform-CASdetec (CRISPRassisted detection). The detection limit of CASdetec for SARS-CoV-2 pseudovirus is 1 × 10 4 copies/mL, with no cross-reactivity observed. Here, we present our assay design and optimization process, which could provide guidance for future CRISPR-based nucleic-acid detection assay development and optimization. To optimize the output of fluorescence signal, we designed and synthesized poly-T fluorescence-quenchers of varying nucleotide lengths, including 4 nt, 5 nt, 7 nt, 12 nt, 17 nt, 22 nt, and 27 nt. Of all the lengths tried, the 7 nt

The ability to create 3D tissues from induced pluripotent stem cells (iPSCs) is poised to revolutionize stem cell research and regenerative medicine, including individualized, patient‐specific stem cell‐based treatments. There are, however, few examples of tissue engineering using iPSCs. Their culture and differentiation is predominantly planar for monolayer cell support or induction of self‐organizing embryoids (EBs) and organoids. Bioprinting iPSCs with advanced biomaterials promises to augment efforts to develop 3D tissues, ideally comprising direct‐write printing of cells for encapsulation, proliferation, and differentiation. Here, such a method, employing a clinically amenable polysaccharide‐based bioink, is described as the first example of bioprinting human iPSCs for in situ expansion and sequential differentiation. Specifically, we have extrusion printed the bioink including iPSCs, alginate (Al; 5% weight/volume [w/v]), carboxymethyl‐chitosan (5% w/v), and agarose (Ag; 1.5% w/v), crosslinked the bioink in calcium chloride for a stable and porous construct, proliferated the iPSCs within the construct and differentiated the same iPSCs into either EBs comprising cells of three germ lineages—endoderm, ectoderm, and mesoderm, or more homogeneous neural tissues containing functional migrating neurons and neuroglia. This defined, scalable, and versatile platform is envisaged being useful in iPSC research and translation for pharmaceuticals development and regenerative medicine.

We construct housing price indices for 120 major cities in China in 2003-2013 based on sequential sales of new homes within the same housing developments. By using these indices and detailed information on mortgage borrowers across these cities, we find enormous housing price appreciation during the decade, which was accompanied by equally impressive growth in household income, except in a few first-tier cities. While bottom-income mortgage borrowers endured severe financial burdens by using price-to-income ratios over eight to buy homes, their participation in the housing market remained steady and their mortgage loans were protected by down payments commonly in excess of 35 percent. As such, the housing market is unlikely to trigger an imminent financial crisis in China, even though it may crash with a sudden stop in the Chinese economy and act as an amplifier of the initial shock.Hanming Fang

Although serum prostate specific antigen (PSA) is a well-established diagnostic tool for prostate cancer (PCa) detection, the definitive diagnosis of PCa is based on the information contained in prostate needle biopsy (PNBX) specimens. To define the proteomic features of PNBX specimens to identify candidate biomarkers for PCa, PNBX specimens from patients with PCa or benign prostatic hyperplasia (BPH) were subjected to comparative proteomic analysis. 2-DE revealed that 52 protein spots exhibited statistically significantly changes among PCa and BPH groups. Interesting spots were identified by MALDI-TOF-MS/MS. The 2 most notable groups of proteins identified included latent androgen receptor coregulators and FKBP4] and enzymes involved in mitochondrial fatty acid b-oxidation (DCI and ECHS1). An imbalance in the expression of peroxiredoxin subtypes was noted in PCa specimens. Furthermore, different post-translationally modified isoforms of HSP27 and HSP70.1 were identified. Importantly, changes in FLNA(7-15), FKBP4, and PRDX4 expression were confirmed by immunoblot analyses. Our results suggest that a proteomics-based approach is useful for developing a more complete picture of the protein profile of PNBX specimen. The proteins identified by this approach may be useful molecular targets for PCa diagnostics and therapeutics. ' 2007 Wiley-Liss, Inc.

The rat is an important animal model in biomedical research, but practical limitations to genetic manipulation have restricted the application of genetic analysis. Here we report the derivation of rat androgenetic haploid embryonic stem cells (RahESCs) as a tool to facilitate such studies. Our approach is based on removal of the maternal pronucleus from zygotes to generate androgenetic embryos followed by derivation of ESCs. The resulting RahESCs have 21 chromosomes, express pluripotency markers, differentiate into three germ layer cells, and contribute to the germline. Homozygous mutations can be introduced by both large-scale gene trapping and precise gene targeting via homologous recombination or the CRISPR-Cas system. RahESCs can also produce fertile rats after intracytoplasmic injection into oocytes and are therefore able to transmit genetic modifications to offspring. Overall, RahESCs represent a practical tool for functional genetic studies and production of transgenic lines in rat.

Carriers that can afford tunable physical and structural changes are envisioned to address critical issues in controlled drug delivery applications. Herein, photo-responsive conjugated polymer nanoparticles (CPNs) functionalized with donor-acceptor Stenhouse adduct (DASA) and folic acid units for controlled drug delivery and imaging are reported. Upon visible-light (λ=550 nm) irradiation, CPNs simultaneously undergo structure, color, and polarity changes that release encapsulated drugs into the cells. The backbone of CPNs favors FRET to DASA units boosting their fluorescence. Notably, drug-loaded CPNs exhibit excellent biocompatibility in the dark, indicating perfect control of the light trigger over drug release. Delivery of both hydrophilic and hydrophobic drugs with good loading efficiency was demonstrated. This strategy enables remotely controlled drug delivery with visible-light irradiation, which sets an example for designing delivery vehicles for non-invasive therapeutics.

Protein misfolding and aberrant aggregations are associated with multiple prevalent and intractable diseases. Inhibition of amyloid assembly is apromising strategy for the treatment of amyloidosis.R eported here is the design and synthesis of areactive conjugated polymer,apoly(p-phenylene vinylene) derivative,f unctionalizedw ith p-nitrophenyl esters (PPV-NP) and it inhibits the assembly of amyloid proteins, degrades preformed fibrils,a nd reduces the cytotoxicity of amyloid aggregations in living cells.PPV-NP is attached to the proteins through hydrophobic interactions and irreversible covalent linkage.P PV-NP also exhibited the capacity to eliminate Ab plaques in brain slices in ex vivo assays.T his work represents an innovative attempt to inhibit protein pathogenic aggregates,and may offer insights into the development of therapeutic strategies for amyloidosis.Proteins are one of the most important basic bio-macromolecules in organisms.T he aberrant assembly of proteins into insoluble amyloid aggregates would disrupt their biological functions and result in the generation of toxic intermediates and amyloidosis,w hich are relevant to ar ange of intractable human disorders such as Alzheimersd isease, Parkinsonsd isease,d ialysis-related amyloidosis,a nd type-2 diabetes. [1][2][3][4][5][6][7] On this account, numerous approaches to inhibit amyloid assembly have emerged, ranging from synthetic and natural small-molecule compounds, [4,8,9] peptides, [10,11] antibodies, [12] and nanoparticles [13,14] to artificial chaperones, [15] which make certain achievements to the inhibition of pathogenic aggregates.H owever,t od ate,t he pharmacological treatments for these diseases are still unsatisfactory. [16] Rational chemical designs to effectively inhibit and disrupt the amyloid assembly are still of great significance.In fact, most previous inhibitors functioned through noncovalent interactions,s uch as hydrophobic interactions, p-p stacking,e lectrostatic interactions,a nd hydrogen bonding. These interactions are intrinsically weak and susceptible to the surrounding environment. [17] Thef luctuation of either pH or temperature may induce the disassembly of inhibitor/ protein complexes,and would make the inhibitors invalid. In contrast, covalent interactions are more chemically stable and not susceptible to the fluctuation of surrounding environment. Reactions between inhibitors and proteins are usually irreversible,and inhibitors could remain attached to proteins for long time.T hus,d eveloping new inhibiting materials for amyloid assembly with acovalent-linking strategy is expected to lead to prolonged duration of inhibition and improved efficiency.T he amphiphilic conjugated polymers are considered pioneering materials in the biomedical field owing to their unique photoelectrical properties. [18][19][20][21][22][23][24] Here,w e designed and synthesized ar eactive conjugated polymer, ap oly(p-phenylene vinylene) derivative,f unctionalized with p-nitrophenyl active esters (PPV-NP) to inhibit protein assembly and disru...