Systematic functional characterization of antisense eRNA of protocadherin α composite enhancer.

Enhancers generate bidirectional noncoding enhancer RNAs (eRNAs) that may regulate gene expression. At present, the eRNA function remains enigmatic. Here, we report a 5' capped antisense eRNA PEARL (Pcdh eRNA associated with R-loop formation) that is transcribed from the protocadherin (Pcdh) α HS5-1 enhancer region. Through loss- and gain-of-function experiments with CRISPR/Cas9 DNA fragment editing, CRISPRi, and CRISPRa, as well as locked nucleic acid strategies, in conjunction with ChIRP, MeDIP, DRIP, QHR-4C, and HiChIP experiments, we found that PEARL regulates Pcdhα gene expression by forming local RNA-DNA duplexes (R-loops) in situ within the HS5-1 enhancer region to promote long-distance chromatin interactions between distal enhancers and target promoters. In particular, increased levels of eRNA PEARL via perturbing transcription elongation factor SPT6 lead to strengthened local three-dimensional chromatin organization within the Pcdh superTAD. These findings have important implications regarding molecular mechanisms by which the HS5-1 enhancer regulates stochastic Pcdhα promoter choice in single cells in the brain.

Effects of family multi-generational relationship on multimorbidity and healthy life expectancy for second generations: insight from the China Health and Retirement Longitudinal Study.

OBJECTIVE: In the context of aging, Chinese families consisting of more than three generations (grandparents, parents, children) are the norm. The second generation (parents) and other family members may establish a downward (contact only with children) or two-way multi-generational relationship (contact with children and grandparents). These multi-generational relationships may have the potential effect on multimorbidity burden and healthy life expectancy in the second generation, but less is known about the direction and intensity of this effect. This study aims to explore this potential effect. METHODS: We obtained longitudinal data from the China Health and Retirement Longitudinal Study from 2011 to 2018, which included 6,768 people. Cox proportional hazards regression was used to assess the association between multi-generational relationships and the number of multimorbidity. The Markov multi-state transition model was used to analyze the relationship between multi-generational relationships and the severity of multimorbidity. The multistate life table was used to calculate healthy life expectancy for different multi-generational relationships. RESULTS: The risk of multimorbidity in two-way multi-generational relationship was 0.830 (95% CIs: 0.715, 0.963) times higher than that in downward multi-generational relationship. For mild multimorbidity burden, downward and two-way multi-generational relationship may prevent aggravation of burden. For severe multimorbidity burden, two-way multi-generational relationship may aggravate the burden. Compared with two-way multi-generational relationship, the second generations with downward multi-generational relationship has a higher healthy life expectancy at all ages. CONCLUSION: In Chinese families with more than three generations, the second generations with severe multimorbidity burden may aggravate the condition by providing support to elderly grandparents, and the support provided by offspring to the second generations plays a vital positive role in improving the quality of life and narrowing the gap between healthy life expectancy and life expectancy.

Slightly acidic electrolyzed water-slurry ice: shelf-life extension and quality maintenance of mackerel (Pneumatophorus japonicus) during chilled storage.

BACKGROUND: Different ice treatments were applied for the preservation of mackerel (Pneumatophorus japonicus). The quality changes of samples treated with flake ice (Control), slurry ice (SI) and slightly acidic electrolyzed water-slurry ice (SAEW-SI) in microbiological, physicochemical, protein characteristic, and sensory evaluation were investigated during chilled storage. RESULTS: SAEW-SI showed a significant advantage for the inhibition of microbial growth, which could extend the shelf-life for another 144 h at least, compared with Control group. SAEW-SI treatment also showed a strong inhibition for the increase in pH, total volatile basic nitrogen (TVB-N), K-value, histamine and metmyoglobin (MetMb) content. Results of texture profile analysis (TPA) and water holding capacity (WHC) indicated that SAEW-SI can obviously suppress the decrease of hardness value, and have a better protective effect on muscle structure compared to flake ice and SI (P < 0.05). During the whole experiment, the highest sensory scores and a* were obtained in the SAEW-SI group, which indicated that SAEW-SI treatment could maintain better sensory characteristics. According to the results of thiobarbituric acid reactive substances (TBARS) and fluorescence spectroscopy analysis, SAEW-SI treatment could effectively retard protein degradation and lipid oxidation compared with Control and SI group. In maintaining the quality of mackerel, SAEW-SI shows a better effect than SI due to the synergistic effect of fence factors. CONCLUSION: The results demonstrated that the shelf-life of mackerel could be extended and the quality of mackerel could be maintained effectively with SAEW-SI treatment during chilled storage. © 2022 Society of Chemical Industry.

Assessment of the efficiency of immobilized degrading microorganisms in removing the organochlorine pesticide residues from agricultural soils.

To investigate the removal of organochlorine pesticide residues by immobilized degrading microbe, indigenous microorganisms from organochlorine pesticide (OCP)-contaminated soils in Chengdu plain, pot experiments were carried out to evaluate the potential of the immobilized complex microbial specific degrading microbe treated with sodium alginate (SA) composite carrier in decontaminating OCP-contaminated soils, and field experiments were also conducted to investigate the enhanced efficiency of immobilized microbial agents on the dissipation of OCPs in the contaminated plots for different cultivation usage. The results showed that the dissipation rate of OCPs in contaminated soils with initial concentrations of 122.24 µg/kg was 89.94% after the addition of 25 mg of immobilized microbial agents at the end of the 90 days of experiment, which was 6.1% higher than that of the compound microbial agents under the same environmental conditions, and the control group without the addition of microbial agents was only 1.18%, while the concentration of OCPs in contaminated soils with initial concentrations of 203.64 µg/kg only decreased to 65.29 µg/kg after the addition of 20 mg of compound microbial agents. In contrast, the soil concentration of immobilized microbial agent treatment group under the same conditions decreased to 52.15 µg/kg. During the field experiment, the enhanced efficiency of immobilized microbial agents on the degradation of OCPs in different cultivation usage was evidently different, showed that the concentration of OCPs in paddy fields (18.60%) > tea gardens (12.17%) ≥ orchards (11.41%) > vegetable fields (6.21%) ≥ dryland (4.79%), which was especially significant in stress environment. Overall, the immobilization treatment obviously improved the degradation potential of OCPs-specific degrading microbe, and the degree of improvement was related to the metabolic activity of the degrading microbe, the addition amount, remediation time, and habitat conditions.

Development of Biodegradable Osteopromotive Citrate-Based Bone Putty.

The burden of bone fractures demands development of effective biomaterial solutions, while additional acute events such as noncompressible bleeding further motivate the search for multi-functional implants to avoid complications including osseous hemorrhage, infection, and nonunion. Bone wax has been widely used in orthopedic bleeding control due to its simplicity of use and conformation to irregular defects; however, its nondegradability results in impaired bone healing, risk of infection, and significant inflammatory responses. Herein, a class of intrinsically fluorescent, osteopromotive citrate-based polymer/hydroxyapatite (HA) composites (BPLP-Ser/HA) as a highly malleable press-fit putty is designed. BPLP-Ser/HA putty displays mechanics replicating early nonmineralized bone (initial moduli from ≈2-500 kPa), hydration induced mechanical strengthening in physiological conditions, tunable degradation rates (over 2 months), low swelling ratios (<10%), clotting and hemostatic sealing potential (resistant to blood pressure for >24 h) and significant adhesion to bone (≈350-550 kPa). Simultaneously, citrate's bioactive properties result in antimicrobial (≈100% and 55% inhibition of S. aureus and E. coli) and osteopromotive effects. Finally, BPLP-Ser/HA putty demonstrates in vivo regeneration in a critical-sized rat calvaria model equivalent to gold standard autograft. BPLP-Ser/HA putty represents a simple, off-the-shelf solution to the combined challenges of acute wound management and subsequent bone regeneration.

Environmental impacts and nutrient distribution routes for food waste separated disposal on large-scale anaerobic digestion/ composting plants.

Centralized biological treatments, i.e., anaerobic digestion (AD) and in-vessel composting (IVC), were supposed to be the promising processes for the disposal of food waste (FW) after source separation, while the systematic benefits were unclear for FW with high water content, salt and oil and thus influenced the selection by the local decision-makers. In this study, two large-scale working AD and IVC plants were compared for environmental impacts, nutrient recovery and economic benefits. For unit amount of FW, 89.26 kg CO2-eq was released in IVC mainly due to 47.89 kWh electricity consumption, and 57.02 kg CO2-eq was produced in AD. With the application of compost and energy recovery, 26.88 and 93.55 kg CO2-eq savings were obtained in IVC and AD, respectively. NH3 emissions were the main contributor to acidification (0.35 kg SO2-eq) in IVC, while AD exerted less impact on acidification (0.09 kg SO2-eq) and nutrient enrichment (0.25 kg NO3-eq) attributed to the counteract of energy recovery. 2029 would be the inflection point for global warming potential in AD with more clean energy applied in electricity mix in China. For nutrient recovery, more C (8.3%), N (37.9%) and P (66.7%) could be recovered in compost, while those were discharged via leachate and biogas residue in AD. The cost of IVC was 16 CNY/t (2.40 USD/t) lower than AD. Combing the three key indexes and the sale routes of products, IVC was recommended to be used in areas dominated by agriculture and forestry industries, and AD was more suitable for large cities.

Prognostic value of myocardial perfusion imaging with D-SPECT camera in patients with ischemia and no obstructive coronary artery disease (INOCA).

BACKGROUND: Myocardial perfusion imaging (MPI) with a novel D-SPECT camera maintains excellent prognostic value compared to conventional SPECT. However, information about the relationship between D-SPECT MPI and the prognosis in patients with ischemia and no obstructive coronary artery disease (INOCA) is limited. The objective of this study was to evaluate the prognostic value of MPI with D-SPECT in INOCA and obstructive coronary artery disease (CAD) patients. METHODS: All consecutive patients with suspected CAD and without prior CAD who underwent D-SPECT MPI and invasive coronary angiography within 3 months were considered. INOCA and obstructive CAD were defined as < 50% and ≥ 50% coronary stenosis, respectively. Patients were followed-up for the occurrence of major adverse cardiac events (MACE: cardiovascular death, nonfatal myocardial infarction, revascularization, stroke, heart failure and angina-related rehospitalization). RESULTS: Among 506 patients, 232 (45.8%) were INOCA patients. A total of 33.2% of the INOCA patients had abnormal D-SPECT MPI, whereas 77.7% of the obstructive CAD patients had abnormal D-SPECT MPI. In both groups, patients with abnormal D-SPECT MPI demonstrated higher MACE rates and lower survival free of MACE. In addition, patients with INOCA and abnormal D-SPECT MPI had a poor prognosis similar to that of the obstructive CAD patients. Cox regression analysis showed that the risk-adjusted hazard ratios for abnormal D-SPECT MPI were 2.55 [1.11-5.87] and 2.06 [1.03-4.10] in the INOCA and obstructive CAD patients, respectively. CONCLUSIONS: D-SPECT MPI provides excellent prognostic information, with a more severe prognosis in patients with abnormal D-SPECT MPI. INOCA patients with abnormal D-SPECT MPI experience a poor prognosis similar to that of patients with obstructive CAD.

Pharmacokinetics, tissue distribution and excretion of five rhubarb anthraquinones in rats after oral administration of effective fraction of anthraquinones from rheum officinale.

Rhubarb, a famous traditional Chinese medicine, shows a wide range of physiological activities and pharmacological benefits. Rhubarb anthraquinones are perceived as the pharmacologically active compounds of Rhubarb, and understanding metabolism of them is crucial to assure safety and effectiveness of clinical application. In this study, the pharmacokinetics, tissue distribution and excretion of five rhubarb anthraquinones (aloe-emodin, rhein, emodin, chrysophanol, physcion) were systematically investigated after oral administration of rhubarb extract to rats.An HPLC method was developed and validated for quantitation of five rhubarb anthraquinones in rat plasma, tissues, urine and faeces to investigate the Pharmacokinetic characteristics. The results showed that the proposed method was suitable for the quantification of five anthraquinones in plasma, tissue and excreta samples with satisfactory linear (r > 0.99), precision (<10%) and recovery (85.12-104.20%). The plasma concentration profiles showed a quick absorption with the mean Tmax of 0.42-0.75 h and t1/2 of 6.60-15.11 h for five anthraquinones. The analytes were widely distributed in most of the tissues. Approximately 0.13-10.59% and 28.47-81.14% of five anthraquinones were recovered in urine and faeces within 132 h post-dosing, which indicated the major elimination route was faeces excretion.In summary, this study lays a foundation for elucidating the pharmacokinetic rule of rhubarb anthraquinone and the important data can provide reliable scientific resource for further research.

Tumor Microenvironment-Responsive Multistaged Nanoplatform for Systemic RNAi and Cancer Therapy.

While RNA interference (RNAi) therapy has demonstrated significant potential for cancer treatment, the effective and safe systemic delivery of RNAi agents such as small interfering RNA (siRNA) into tumor cells in vivo remains challenging. We herein reported a unique multistaged siRNA delivery nanoparticle (NP) platform, which is comprised of (i) a polyethylene glycol (PEG) surface shell, (ii) a sharp tumor microenvironment (TME) pH-responsive polymer that forms the NP core, and (iii) charge-mediated complexes of siRNA and tumor cell-targeting- and penetrating-peptide-amphiphile (TCPA) that are encapsulated in the NP core. When the rationally designed, long circulating polymeric NPs accumulate in tumor tissues after intravenous administration, the targeted siRNA-TCPA complexes can be rapidly released via TME pH-mediated NP disassembly for subsequent specific targeting of tumor cells and cytosolic transport, thus achieving efficient gene silencing. In vivo results further demonstrate that the multistaged NP delivery of siRNA against bromodomain 4 (BRD4), a recently discovered target protein that regulates the development and progression of prostate cancer (PCa), can significantly inhibit PCa tumor growth.

MIL-101-SO3H: a highly efficient Brønsted acid catalyst for heterogeneous alcoholysis of epoxides under ambient conditions.

For the first time, a ∼100% sulfonic acid functionalized metal-organic framework (MOF), MIL-101-SO3H, with giant pores has been prepared by a hydrothermal process followed by a facile postsynthetic HCl treatment strategy. The replete readily accessible Lewis acidic and especially Brønsted acidic sites distributed throughout the framework as well as high stability endow the resultant MOF exceptionally high efficiency and recyclability, which surpass all other MOF-based catalysts, for the ring opening of epoxides with alcohols (especially, methanol) as nucleophiles under ambient conditions.

Harnessing accurate mitochondrial DNA base editing mediated by DdCBEs in a predictable manner.

Introduction: Mitochondrial diseases caused by mtDNA have no effective cures. Recently developed DddA-derived cytosine base editors (DdCBEs) have potential therapeutic implications in rescuing the mtDNA mutations. However, the performance of DdCBEs relies on designing different targets or improving combinations of split-DddA halves and orientations, lacking knowledge of predicting the results before its application. Methods: A series of DdCBE pairs for wide ranges of aC or tC targets was constructed, and transfected into Neuro-2a cells. The mutation rate of targets was compared to figure out the potential editing rules. Results: It is found that DdCBEs mediated mtDNA editing is predictable: 1) aC targets have a concentrated editing window for mtDNA editing in comparison with tC targets, which at 5'C8-11 (G1333) and 5'C10-13 (G1397) for aC target, while 5'C4-13 (G1333) and 5'C5-14 (G1397) for tC target with 16bp spacer. 2) G1333 mediated C>T conversion at aC targets in DddA-half-specific manner, while G1333 and G1397 mediated C>T conversion are DddA-half-prefer separately for tC and aC targets. 3) The nucleotide adjacent to the 3' end of aC motif affects mtDNA editing. Finally, by the guidance of these rules, a cell model harboring a pathogenic mtDNA mutation was constructed with high efficiency and no bystander effects. Discussion: In summary, this discovery helps us conceive the optimal strategy for accurate mtDNA editing, avoiding time- and effort-consuming optimized screening jobs.

Engineering a robust and anisotropic cardiac-specific extracellular matrix scaffold for cardiac patch tissue engineering.

Extracellular matrix (ECM) fabricated using human induced pluripotent stem cells (hiPSCs)-derived cardiac fibroblasts (hiPSC-CFs) could serve as a completely biological scaffold for an engineered cardiac patch, leveraging the unlimited source and outstanding reproducibility of hiPSC-CFs. Additionally, hiPSC-CF-derived ECM (hiPSC-CF-ECM) holds the potential to enhance maturation of exogenous cardiomyocytes, such as hiPSC-derived cardiomyocytes (hiPSC-CMs), by providing a microenvironment rich in cardiac-specific biochemical and signaling cues. However, achieving sufficient robustness of hiPSC-CF-ECM is challenging. This study aims to achieve appropriate ECM deposition, scaffold thickness, and mechanical strength of an aligned hiPSC-CF-ECM by optimizing the culture period, ranging from 2 to 10 weeks, of hiPSC-CFs grown on micro-grated substrates, which can direct the alignment of both hiPSC-CFs and their secreted ECM. The hiPSC-CFs demonstrated a production rate of 13.5 µg ECM per day per 20,000 cells seeded. An anisotropic nanofibrous hiPSC-CF-ECM scaffold with a thickness of 20.0 ± 2.1 µm was achieved after 6 weeks of culture, followed by decellularization. Compositional analysis through liquid chromatography-mass spectrometry (LC-MS) revealed the presence of cardiac-specific fibrillar collagens, non-fibrillar collagens, and matricellular proteins. Uniaxial tensile stretching of the hiPSC-CF-ECM scaffold indicated robust tensile resilience. Finally, hiPSCs-CMs cultured on the hiPSC-CF-ECM exhibited alignment following the guidance of ECM nanofibers and demonstrated mature organization of key structural proteins. The culture duration of the anisotropic hiPSC-CF-ECM was successfully refined to achieve a robust scaffold containing structural proteins that resembles cardiac microenvironment. This completely biological, anisotropic, and cardiac-specific ECM holds great potential for cardiac patch engineering.

Simulated phytoremediation by root exudates of Sudan grass of soil organochlorine pesticides: impact on the rhizosphere microbial community.

The present work aims to study the efficiency of root exudates of Sudan grass on the degradation of organochlorine pesticides (OCPs) and the consequent impact on the microbial and ecological characteristics of the soil, including population composition, quantity dynamics, and community structure. Pot experiments were carried out to study the effect of root exudates on the degradation of OCPs at initial concentrations ranging from 66.67 to 343.61 mg/kg. In addition, the influence of root exudates on the rhizosphere microbial growth and their community structure was studied by monitoring the microbial biomass carbon, microbial biomass nitrogen, and phospholipid fatty acids (PLFAs) in the soils. In the range of OCP content (66.67 ~ 343.61 mg/kg), the soil-microbial system mediated by root exudates significantly promoted the removal of OCP pollutants. The removal rate of OCPs in the rhizosphere soil (TR2) was as high as 79.32%, 36.86% higher than that in the OCP-contaminated group (TR1) and 60.63% higher than that in the sterilized treatment group (CK). Under the same treatment conditions (pollution level and additive dose), the enhanced removal rate of HCHs, toxaphene, HCB, aldrin, and γ-chlordane by root exudates was much higher than the total amount of OCPs, while the extent of enhanced dissipation of DDTs, mirex, endosulfanI, dieldrin, and heptachlor epoxide was always lower than that in the corresponding soils. During the experiment, the phospholipid fatty acid content of bacteria was dominant, followed by that of fungi, and their variation trend was consistent with the degradation characteristics of OCPs in soil. Root exudates of Sudan grass might change the rhizosphere bacterial and fungal community structure during the process of phytoremediation, leading to enhanced OCP degradation.

A psychometric evaluation of Chinese chronic hepatitis B virus infection-related stigma scale using classical test theory and item response theory.

Purpose: To validate the hepatitis B virus infection-related stigma scale (HBVISS) using Classical Test Theory and Item Response Theory in a sample of Chinese chronic HBV carriers. Methods: Feasibility, internal consistency reliability, split-half reliability and construct validity were evaluated using a cross-sectional validation study (n = 1,058) in Classical Test Theory. Content validity was assessed by COnsensus-based Standards for the selection of health Measurement INstruments (COSMIN) criteria. The Item Response Theory (IRT) model parameters were estimated using Samejima's graded response model, after which item response category characteristic curves were drawn. Item information, test information, and IRT-based marginal reliability were calculated. Measurement invariance was assessed using differential item functioning (DIF). SPSS and R software were used for the analysis. Results: The response rate reached 96.4% and the scale was completed in an average time of 5 min. Content validity of HBVISS was sufficient (+) and the quality of the evidence was high according to COSMIN criteria. Confirmatory factor analysis showed acceptable goodness-of-fit (χ 2/df = 5.40, standardized root mean square residual = 0.057, root mean square error of approximation = 0.064, goodness-of-fit index = 0.902, comparative fit index = 0.925, incremental fit index = 0.926, and Tucker-Lewis index = 0.912). Cronbach's α fell in the range of 0.79-0.89 for each dimension and 0.93 for the total scale. Split-half reliability was 0.96. IRT discrimination parameters were estimated to range between 0.959 and 2.333, and the threshold parameters were in the range-3.767 to 3.894. The average score for test information was 12.75 (information >10) when the theta level reached between-4 and + 4. The IRT-based marginal reliability was 0.95 for the total scale and fell in the range of 0.83-0.91 for each dimension. No measurement invariance was detected (d-R 2 < 0.02). Conclusion: HBVISS exhibited good feasibility, reliability, validity, and item quality, making it suitable for assessing chronic Hepatitis B virus infection-related stigma.

A spiral microfluidic device for rapid sorting, trapping, and long-term live imaging of Caenorhabditis elegans embryos.

Caenorhabditis elegans embryos have been widely used to study cellular processes and developmental regulation at early stages. However, most existing microfluidic devices focus on the studies of larval or adult worms rather than embryos. To accurately study the real-time dynamics of embryonic development under different conditions, many technical barriers must be overcome; these can include single-embryo sorting and immobilization, precise control of the experimental environment, and long-term live imaging of embryos. This paper reports a spiral microfluidic device for effective sorting, trapping, and long-term live imaging of single C. elegans embryos under precisely controlled experimental conditions. The device successfully sorts embryos from a mixed population of C. elegans at different developmental stages via Dean vortices generated inside a spiral microchannel and traps the sorted embryos at single-cell resolution through hydrodynamic traps on the sidewall of the spiral channel for long-term imaging. Through the well-controlled microenvironment inside the microfluidic device, the response of the trapped C. elegans embryos to mechanical and chemical stimulation can be quantitatively measured. The experimental results show that a gentle hydrodynamic force would induce faster growth of embryos, and embryos developmentally arrested in the high-salinity solution could be rescued by the M9 buffer. The microfluidic device provides new avenues for easy, rapid, high-content screening of C. elegans embryos.

Detergent-Based Decellularization for Anisotropic Cardiac-Specific Extracellular Matrix Scaffold Generation.

Cell-derived extracellular matrix (ECM) has become increasingly popular in tissue engineering applications due to its ability to provide tailored signals for desirable cellular responses. Anisotropic cardiac-specific ECM scaffold decellularized from human induced pluripotent stem cell (hiPSC)-derived cardiac fibroblasts (hiPSC-CFs) mimics the native cardiac microenvironment and provides essential biochemical and signaling cues to hiPSC-derived cardiomyocytes (hiPSC-CMs). The objective of this study was to assess the efficacy of two detergent-based decellularization methods: (1) a combination of ethylenediaminetetraacetic acid and sodium dodecyl sulfate (EDTA + SDS) and (2) a combination of sodium deoxycholate and deoxyribonuclease (SD + DNase), in preserving the composition and bioactive substances within the aligned ECM scaffold while maximumly removing cellular components. The decellularization effects were evaluated by characterizing the ECM morphology, quantifying key structural biomacromolecules, and measuring preserved growth factors. Results showed that both treatments met the standard of cell removal (less than 50 ng/mg ECM dry weight) and substantially preserved major ECM biomacromolecules and growth factors. The EDTA + SDS treatment was more time-efficient and has been determined to be a more efficient method for generating an anisotropic ECM scaffold from aligned hiPSC-CFs. Moreover, this cardiac-specific ECM has demonstrated effectiveness in supporting the alignment of hiPSC-CMs and their expression of mature structural and functional proteins in in vitro cultures, which is crucial for cardiac tissue engineering.

Correction: A spiral microfluidic device for rapid sorting, trapping, and long-term live imaging of Caenorhabditis elegans embryos.

[This corrects the article DOI: 10.1038/s41378-023-00485-4.].

Geometric Mismatch Promotes Anatomic Repair in Periorbital Bony Defects in Skeletally Mature Yucatan Minipigs.

Porous tissue-engineered 3D-printed scaffolds are a compelling alternative to autografts for the treatment of large periorbital bone defects. Matching the defect-specific geometry has long been considered an optimal strategy to restore pre-injury anatomy. However, studies in large animal models have revealed that biomaterial-induced bone formation largely occurs around the scaffold periphery. Such ectopic bone formation in the periorbital region can affect vision and cause disfigurement. To enhance anatomic reconstruction, geometric mismatches are introduced in the scaffolds used to treat full thickness zygomatic defects created bilaterally in adult Yucatan minipigs. 3D-printed, anatomically-mirrored scaffolds are used in combination with autologous stromal vascular fraction of cells (SVF) for treatment. An advanced image-registration workflow is developed to quantify the post-surgical geometric mismatch and correlate it with the spatial pattern of the regenerating bone. Osteoconductive bone growth on the dorsal and ventral aspect of the defect enhances scaffold integration with the native bone while medio-lateral bone growth leads to failure of the scaffolds to integrate. A strong positive correlation is found between geometric mismatch and orthotopic bone deposition at the defect site. The data suggest that strategic mismatch >20% could improve bone scaffold design to promote enhanced regeneration, osseointegration, and long-term scaffold survivability.

Atomic force microscopy (AFM) and its applications to bone-related research.

Bone consists of organic (mostly collagen) and inorganic (mostly bioapatite mineral) components that are organized into hierarchical structures from nano-to macro-scales that provide load-bearing functions. The structures and properties of bone are affected by bone remodeling activities, which are affected by mechanotransduction, a process through which mechanical signals are converted to biochemical signals in cellular signaling. Atomic Force Microscopy (AFM) technique can be used to characterize the surface morphology and mechanical properties of the specimens and can achieve atomic resolution in the resulting images. Therefore, the AFM technique has been applied in bone research and has provided new understandings of the structures and properties of hierarchical structures in bone across multiple length scales. This review begins by introducing the tip-surface interactions and the operation modes of AFM, including the recently developed sub-resonance modes, including PeakForce Tapping mode. Then the contact adhesion theories used in analyzing AFM data are reviewed, followed by a systematic review of the applications of the AFM technique to bone and bone-related tissues and cells, including surface morphology imaging, contact indentation testing, and other mechanical tests. The applications of sub-resonance tapping mode to bone and other biological molecules, cells, and tissues are also reviewed.

A biodegradable 3D woven magnesium-based scaffold for orthopedic implants.

Porous Magnesium (Mg) is a promising biodegradable scaffold for treating critical-size bone defects, and as an essential element for human metabolism, Mg has shown sufficient biocompatibility. Its elastic moduli and yield strengths are closer to those of cortical bone than common, inert metallic implants, effectively reducing stress concentrations around host tissue as well as stress shielding. More importantly, Mg can degrade and be absorbed in the human body in a safe and controlled manner, thereby reducing the need for second surgeries to remove implants. The development of porous Mg scaffolds via conventional selective laser melting techniques has been limited due to Mg's low boiling point, high vapor pressures, high reactivity, and non-ideal microstructures in additively manufactured parts. Here we present an exciting alternative to conventional additive techniques: 3D weaving with Mg wires that have controlled chemistries and microstructures. The weaving process offers high throughput manufacturing as well as porous architectures that can be optimized for stiffness and porosity with topology optimization. Once woven, we dip-coat the weaves with polylactic acid to enhance their strength and corrosion resistance. Following fabrication, we characterize their mechanical properties, corrosion behavior, and cell compatibilityin vitro, and we use an intramuscular implantation model to evaluate theirin vivocorrosion behavior and tissue response.