Functionalization of Covalent Organic Frameworks with Peptides by Polymer-Assisted Surface Modification and the Application for Protein Detection.

Although covalent organic frameworks (COFs) have received extensive attention for biomedical research due to their unique properties, their application is still hindered by the challenges of incorporating COFs with functional biomolecules. Since peptides have shown advantages in biomedical applications, herein, we propose the functionalization of COFs with peptides by a polymer-assisted surface modification strategy. Furthermore, a method based on the peptide-functionalized COFs for protein detection has also been developed to demonstrate their application potential. With the help of the polymers, peptides and horseradish peroxidase are attached onto COFs with a high surface density, and the developed method has achieved simple and sensitive detection of the secreted protein acidic and rich in cysteine. We speculate that the facile method proposed in this work to prepare peptide-functionalized COFs can not only benefit protein detection but also promote more biomedical applications of COFs.

Functionalization of Covalent Organic Frameworks with DNA via Covalent Modification and the Application to Exosomes Detection.

The functionalization of covalent organic frameworks (COFs) with biomacromolecules can extend their functions, which is the premise of their application in biomedical research. However, strategies to functionalize COFs with biomacromolecules, which can ensure the stability in complex medium and minimize the undesired effects, are still lacking. In this work, we have proposed a strategy to functionalize COFs with DNA by covalently linking DNA to the functional group on the COF surface through Cu(I)-catalyzed azide/alkyne cycloaddition (CuAAC) reaction. The as-prepared DNA-functionalized COFs (DNA-COFs) can exhibit good hybridization ability and cargo loading ability; thus, we have designed a DNA-COF-based nanoprobe and then fabricated an electrochemical biosensor for the detection of exosomes. In this design, the functionalization with DNA enables COFs to recognize and capture exosomes, and the encapsulation of a large number of methylene blue (MB) in COFs facilitates signal amplification, which can enhance the sensitivity of the biosensor. Moreover, by simply replacing the oligonucleotide sequences, the strategy proposed here can generally be used to build different DNA-COFs with diverse functions for broader biomedical applications.

Visual naked-eye detection of SARS-CoV-2 RNA based on covalent organic framework capsules.

The ongoing outbreak of coronavirus disease 2019 (COVID-19) caused by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has highlighted that new diagnosis technologies are crucial for controlling the spread of the disease. Especially in the resources-limit region, conveniently operated detection methods such as "naked-eye" detection are urgently required that no instrument is needed. Herein, we have designed a novel and facile strategy to fabricate covalent organic framework (COF) capsules, which can be utilized to establish a new colorimetric assay for naked-eye detection of SARS-CoV-2 RNA. Specifically, we employ the digestible ZIF-90 as the sacrificial template to prepare the hollow COF capsules for horseradish peroxidase (HRP) encapsulation. The fabricated COF capsules can provide an appropriate microenvironment for the enzyme molecules, which may improve the conformational freedom of enzymes, enhance the mass transfer, and endow the enzyme with high environmental resistance. With such design, the proposed assay exhibits outstanding analytical performance for the detection of SARS-CoV-2 RNA in the linear range from 5 pM to 50 nM with a detection limit of 0.28 pM which can go parallel to qTR-PCR analysis. Our method also possesses excellent selectivity and reproducibility. Moreover, this method can also be served to analyze the clinical samples, and can successfully differentiate COVID-19 patients from healthy people, suggesting the promising potential in clinical diagnosis.

[Prenatal diagnosis and genetic analysis of 17 fetuses with skeletal dysplasia].

OBJECTIVE: To explore strategies of prenatal genetic testing for fetuses featuring abnormal skeletal development. METHODS: Clinical data of 17 fetuses with skeletal dysplasia was collected. The results of genetic testing and outcome of pregnancy were analyzed. RESULTS: For 12 fetuses, the femur-to-foot length ratio was less than 0.9. Thirteen fetuses had a positive finding by genetic testing. One fetus was diagnosed with chromosomal aneuploidy, three were diagnosed with microdeletion/microduplications, and nine were diagnosed with hereditary bone diseases due to pathological variants of FGFR3, COL1A2, GPX4 or ALPL genes. CONCLUSION: For fetuses with skeletal dysplasia characterized by short femur, in addition to chromosomal karyotyping and microarray analysis, sequencing of FGFR3 and other bone disease-related genes can improve the diagnostic rate.

Individual Cloud-Based Fingerprint Operation Platform for Latent Fingerprint Identification Using Perovskite Nanocrystals as Eikonogen.

Fingerprint formed through lifted papillary ridges is considered the best reference for personal identification. However, the currently available latent fingerprint (LFP) images often suffer from poor resolution, have a low degree of information, and require multifarious steps for identification. Herein, an individual Cloud-based fingerprint operation platform has been designed and fabricated to achieve high-definition LFPs analysis by using CsPbBr3 perovskite nanocrystals (NCs) as eikonogen. Moreover, since CsPbBr3 NCs have a special response to some fingerprint-associated amino acids, the proposed platform can be further used to detect metabolites on LFPs. Consequently, in virtue of Cloud computing and artificial intelligence (AI), this study has demonstrated a champion platform to realize the whole LFP identification analysis. In a double-blind simulative crime game, the enhanced LFP images can be easily obtained and used to lock the suspect accurately within one second on a smartphone, which can help investigators track the criminal clue and handle cases efficiently.

Coating a DNA self-assembled monolayer with a metal organic framework-based exoskeleton for improved sensing performance.

The formation of DNA self-assembled monolayers (SAMs) is one of the most popular ways to attach DNA molecules onto Au surfaces and is extensively used in many fields, especially in biosensing. However, the relatively poor stability of DNA SAMs (e.g., after long-term storage or under harsh environmental conditions) greatly limits their use in real applications. Herein, a new strategy is reported to protect the DNA SAMs by using a metal organic framework (MOF)-based exoskeleton. Taking electrochemical DNA (E-DNA) sensors as an example, we have systematically studied the stability of various DNA probes from the simple single-stranded DNA to a complex DNA nanostructure on the Au electrode surface. We have found that different DNA probes lead to various MOF profiles and the formed MOFs can be conveniently removed by simple acidic water rinse. Thanks to the exoskeleton, the stability of DNA SAMs is significantly enhanced and the DNA probes can be insulated from heat, nuclease, and varying ionic strengths, greatly extending the shelf-life of E-DNA sensors and indirectly improving their sensing performance. More importantly, the secondary structures of DNA probes can also be well preserved. The longstanding stability is of particular importance to biosensors; thus they can be facilely handled, transported, and stored in a resource-limited setting without compromising the analytical performance of biosensors.

Design of DNA nanostructure-based interfacial probes for the electrochemical detection of nucleic acids directly in whole blood.

Here we report a robust and sensitive DNA nanostructure-based electrochemical (E-nanoDNA) sensor that utilizes tetrahedral DNA nanostructures (TDNs) as an interfacial probe to detect biomolecules in a single-step procedure. In this study, we have firstly demonstrated that the use of TDNs can significantly suppress electrochemical background signals compared to traditional linear DNA probes upon introduction of base mismatches in the edges of TDNs. After further optimization of the two functional strands in the TDNs, quantitative, one-step detection of DNA can be achieved in the picomolar range in less than 10 min, and directly in complex media. Moreover, the baseline drift of this biosensor can be greatly decreased even after several hours in flowing whole blood in vitro, which suggests that the sensor holds potential to be employed in live animals. Furthermore, through replacing functional strands with aptamers or other DNA elements, this E-nanoDNA sensor can be easily used to probe various analytes, broadening the application range of the proposed sensor.

Exacerbation of primary intestinal lymphangiectasia during late pregnancy and recovery after delivery: A case report and literature review.

RATIONALE: Primary intestinal lymphangiectasia (PIL) is a rare disease characterized by dilated intestinal lacteals resulting in lymph leakage into the small bowel lumen. Main clinical features include intermittent diarrhea, hypoproteinemia. Scattered case reports suggested that PIL is compatible to pregnancy, but with increased complications. PATIENT CONCERNS: A 34-year-old woman with endoscopically diagnosed PIL presented to antenatal our clinic at 10 weeks into gestation. She reported strict adherence to low-fat/high-protein diet with medium-chain triglycerides (MCTs) supplementation. She was general well except for moderate edema and hypoalbuminemia. At 33 weeks, she developed diarrhea, nausea, and vomiting, with decreased fetal movements. One week later, she had an asthma attack. Nonstress test showed frequent variable deceleration. DIAGNOSES: The diagnosis of PIL was established endoscopically 8 years earlier. INTERVENTIONS: Hypoalbuminemia was corrected with intravenous albumin administration. She also received corticosteroid therapy to promote fetal lung maturation in anticipation to early termination of the pregnancy. OUTCOMES: A cesarean section was carried out at 34 weeks due to fetal distress. The baby girl was apparently healthy: weighing 2160 g, with an Apgar score of 9 at both 1 and 5 minutes. Symptoms dissipated rapidly after the delivery. The last follow-up visit at 15 months was unremarkable for both the mother and infant. LESSONS: PIL could be compatible with pregnancy, but requires strict adherence to dietary treatment, proper management of the symptoms (e.g., hypoalbuminemia), particularly during late gestation.

[Treatment of lumbar instability with transforaminal lumbar interbody fusion (with single cage) combined with unilateral pedicle screw fixation].

OBJECTIVE: To explore the clinical effect of transforaminal lumbar interbody fusion (with single cage) combined with unilateral pedicle screw fixation in treating lumbar instability. METHODS: The clinical data of 50 patients with lumbar instability were retrospectively analyzed. They underwent treatment and obtained following up more than 8 months from 2009 to 2012. All patients complicated with refractory or recurrent lower back pain, and unilateral primarily or unilateral lower limb radiation pain, X-ray and CT films showed lumbar instability. The patients were respectively treated with transforaminal lumbar interbody fusion (with single cage) combined with unilateral or bilateral pedicle screw fixation. According to different fixation methods, they divided into unilateral fixation group and bilateral fixation group. There were 20 patients with 22 intervertebral spaces in unilateral fixation group, 8 males and 12 females, aged from 26 to 66 years old, 2 cases with isthmic spondylolisthesis of degree I, 8 cases with degenerative spondylolisthesis, 10 cases with lumbar disc herniation; fusion location with L3,4 was in 1 case, L4,5 was in 12 cases, L5S1 was in 9 cases. There were 30 patients with 30 intervertebral spaces in bilateral fixation group, 14 males and 16 females, aged from 41 to 62 years old, 4 cases with isthmic spondylolisthesis of degree I,14 cases with degenerative spondylolisthesis, 12 cases with lumbar disc herniation; fusion location with L3,4 was in 3 cases, L4,5 was in 15 case, L5S1 was in 12 cases. Operation time, intraoperative blood loss, postoperative drainage, complications were analyzed and intervertebral height, lordosis angle changes, fusion rate and clinical effect were compared between two groups. RESULTS: All incisions obtained primary healing,lower limb radiation pain and low back pain disappeared basically, no infection, endorachis injury was found. Foot drop occurred in one case of bilateral fixation group and no iatrogenic neurological symptom was found in unilateral fixation group. All patients were followed up from 8 to 18 months with an average of (10.8?4.3)months. Ac- cording to JOA score improvement rate (RIS) to assess clinical effect, all patients got excellent and good results, there was no statistically significant difference between two groups. Two methods can both effectively increase the pathological intervertebral height. Unilateral fixation group was better than bilateral fixation group in aspect of operation time, intraoperative blood loss and postoperative drainage. CONCLUSION: With strict indication and good skills, transforaminal lumbar interbody fusion (with single cage) combined with unilateral pedicle screw fixation in treating lumbar instability has advantages of smaller traumatic, less blood loss, faster recovery for the patient and can reduce the economic cost.