Injectable catalyst-free “click” organic-inorganic nanohybrid (click-ON) cement for minimally invasive in vivo bone repair

Large bone defects are a medical concern as these are often unable to heal spontaneously, based on the host bone repair mechanisms. In their treatment, bone tissue engineering techniques represent a promising approach by providing a guide for osseous regeneration. As bioactive glasses proved to have osteoconductive and osteoinductive properties, the aim of our study was to evaluate by histologic examination, the differences in the healing of critical-sized calvarial bone defects filled with bioactive glass combined with adipose-derived mesenchymal stem cells, compared to negative controls. We used 16 male Wistar rats subjected to a specific protocol based on which 2 calvarial bone defects were created in each animal, one was filled with Bon Alive S53P4 bioactive glass and adipose-derived stem cells and the other one was considered control. At intervals of one week during the following month, the animals were euthanized and the specimens from bone defects were histologically examined and compared. The results showed that this biomaterial was biocompatible and the first signs of osseous healing appeared in the third week. Bone Alive S53P4 bioactive glass could be an excellent bone substitute, reducing the need of bone grafts.

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Ferromagnetic soft catheter robots for minimally invasive bioprinting

Nature Communications ◽

10.1038/s41467-021-25386-w ◽

2021 ◽

Vol 12 (1) ◽

Author(s):

Cheng Zhou ◽

Youzhou Yang ◽

Jiaxin Wang ◽

Qingyang Wu ◽

Zhuozhi Gu ◽

...

Keyword(s):

Minimally Invasive ◽

The Body ◽

Magnetic Actuation ◽

Internal Organs ◽

Planar Surfaces ◽

Reinforced Polymer ◽

Direct Fabrication ◽

Digitally Controlled

AbstractIn vivo bioprinting has recently emerged as a direct fabrication technique to create artificial tissues and medical devices on target sites within the body, enabling advanced clinical strategies. However, existing in vivo bioprinting methods are often limited to applications near the skin or require open surgery for printing on internal organs. Here, we report a ferromagnetic soft catheter robot (FSCR) system capable of in situ computer-controlled bioprinting in a minimally invasive manner based on magnetic actuation. The FSCR is designed by dispersing ferromagnetic particles in a fiber-reinforced polymer matrix. This design results in stable ink extrusion and allows for printing various materials with different rheological properties and functionalities. A superimposed magnetic field drives the FSCR to achieve digitally controlled printing with high accuracy. We demonstrate printing multiple patterns on planar surfaces, and considering the non-planar surface of natural organs, we then develop an in situ printing strategy for curved surfaces and demonstrate minimally invasive in vivo bioprinting of hydrogels in a rat model. Our catheter robot will permit intelligent and minimally invasive bio-fabrication.

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Bone defect reconstruction via endochondral ossification: A developmental engineering strategy

Journal of Tissue Engineering ◽

10.1177/20417314211004211 ◽

2021 ◽

Vol 12 ◽

pp. 204173142110042

Author(s):

Rao Fu ◽

Chuanqi Liu ◽

Yuxin Yan ◽

Qingfeng Li ◽

Ru-Lin Huang

Keyword(s):

Bone Regeneration ◽

Bone Defect ◽

Bone Repair ◽

Endochondral Ossification ◽

Current Knowledge ◽

Endochondral Bone ◽

Defect Reconstruction ◽

Hypoxic Conditions ◽

Bone Defect Reconstruction

Traditional bone tissue engineering (BTE) strategies induce direct bone-like matrix formation by mimicking the embryological process of intramembranous ossification. However, the clinical translation of these clinical strategies for bone repair is hampered by limited vascularization and poor bone regeneration after implantation in vivo. An alternative strategy for overcoming these drawbacks is engineering cartilaginous constructs by recapitulating the embryonic processes of endochondral ossification (ECO); these constructs have shown a unique ability to survive under hypoxic conditions as well as induce neovascularization and ossification. Such developmentally engineered constructs can act as transient biomimetic templates to facilitate bone regeneration in critical-sized defects. This review introduces the concept and mechanism of developmental BTE, explores the routes of endochondral bone graft engineering, highlights the current state of the art in large bone defect reconstruction via ECO-based strategies, and offers perspectives on the challenges and future directions of translating current knowledge from the bench to the bedside.

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1700 nm optical coherence microscopy enables minimally invasive, label-free, in vivo optical biopsy deep in the mouse brain

Light Science & Applications ◽

10.1038/s41377-021-00586-7 ◽

2021 ◽

Vol 10 (1) ◽

Author(s):

Jun Zhu ◽

Hercules Rezende Freitas ◽

Izumi Maezawa ◽

Lee-way Jin ◽

Vivek J. Srinivasan

Keyword(s):

Minimally Invasive ◽

Mouse Brain ◽

Numerical Aperture ◽

Optical Biopsy ◽

Optical Coherence ◽

Label Free ◽

Optical Coherence Microscopy ◽

Minimal Invasiveness ◽

Cortical Regions

AbstractIn vivo, minimally invasive microscopy in deep cortical and sub-cortical regions of the mouse brain has been challenging. To address this challenge, we present an in vivo high numerical aperture optical coherence microscopy (OCM) approach that fully utilizes the water absorption window around 1700 nm, where ballistic attenuation in the brain is minimized. Key issues, including detector noise, excess light source noise, chromatic dispersion, and the resolution-speckle tradeoff, are analyzed and optimized. Imaging through a thinned-skull preparation that preserves intracranial space, we present volumetric imaging of cytoarchitecture and myeloarchitecture across the entire depth of the mouse neocortex, and some sub-cortical regions. In an Alzheimer’s disease model, we report that findings in superficial and deep cortical layers diverge, highlighting the importance of deep optical biopsy. Compared to other microscopic techniques, our 1700 nm OCM approach achieves a unique combination of intrinsic contrast, minimal invasiveness, and high resolution for deep brain imaging.

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Effect of valproic acid on functional bleb morphology in a rabbit model of minimally invasive surgery

British Journal of Ophthalmology ◽

10.1136/bjophthalmol-2020-318691 ◽

2021 ◽

pp. bjophthalmol-2020-318691

Author(s):

Zhu Li Yap ◽

Li-Fong Seet ◽

Stephanie WL Chu ◽

Li Zhen Toh ◽

Farah Ilyana Ibrahim ◽

...

Keyword(s):

Valproic Acid ◽

Cell Growth ◽

Minimally Invasive ◽

Transforming Growth Factor Beta ◽

Transforming Growth Factor ◽

Rabbit Model ◽

Terminal Deoxynucleotidyl Transferase ◽

Label Free ◽

Collagen Fibres

AbstractPurposeTo determine the effect of valproic acid (VPA) on bleb morphology and scar characteristics in a rabbit model of minimally invasive glaucoma surgery (MIGS).MethodsNine New Zealand white rabbits were subjected to MIGS with intraoperative implantation of the PreserFlo MicroShunt. Rabbits were then administered with subconjunctival injections of phosphate buffered saline (PBS) (n=4) or with VPA (n=5). Bleb morphology was examined by slit-lamp biomicroscopy and in vivo confocal microscopy. Postoperative day 28 tissues were examined by immunohistochemical evaluation and label-free multiphoton microscopy to visualise the collagen matrix, by terminal deoxynucleotidyl transferase dUTP nick-end labelling assay and immunofluorescent labelling for Ki67 expression to detect apoptosis and cell growth, and by real-time quantitative PCR to measure Col1a1, Fn, and Smad6 transcript expression.ResultsVPA-treated blebs were detectable on day 28, while the PBS-treated blebs were not detectable by day 14. VPA-treated blebs were diffuse, extended posteriorly with near normal conjunctival vascularity and featured a combination of reticular/blurred stromal pattern with evidence of relatively large stromal cysts. Instead of the deposition of thick, disorganised collagen fibres characteristic of the PBS bleb, the VPA bleb contained conspicuously thinner collagen fibres which were associated with similarly thinner fibronectin fibres. In corroboration, Col1a1 and Fn mRNA expression was reduced in the VPA blebs, while increased Smad6 expression implicated the disruption of the transforming growth factor beta pathway. Apoptosis and cell growth profiles appeared similar with both treatments.ConclusionsThe results support the application of VPA to enhance bleb morphology associated with good bleb function in MIGS with no apparent cytotoxicity.

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Zn-Containing Membranes for Guided Bone Regeneration in Dentistry

Polymers ◽

10.3390/polym13111797 ◽

2021 ◽

Vol 13 (11) ◽

pp. 1797

Author(s):

Manuel Toledano ◽

Marta Vallecillo-Rivas ◽

María T. Osorio ◽

Esther Muñoz-Soto ◽

Manuel Toledano-Osorio ◽

...

Keyword(s):

Mechanical Properties ◽

Bone Regeneration ◽

Bone Healing ◽

Bone Repair ◽

Complex Modulus ◽

Bacterial Colonization ◽

Guided Bone Regeneration ◽

M2 Macrophage

Barrier membranes are employed in guided bone regeneration (GBR) to facilitate bone in-growth. A bioactive and biomimetic Zn-doped membrane with the ability to participate in bone healing and regeneration is necessary. The aim of the present study is to state the effect of doping the membranes for GBR with zinc compounds in the improvement of bone regeneration. A literature search was conducted using electronic databases, such as PubMed, MEDLINE, DIMDI, Embase, Scopus and Web of Science. A narrative exploratory review was undertaken, focusing on the antibacterial effects, physicochemical and biological properties of Zn-loaded membranes. Bioactivity, bone formation and cytotoxicity were analyzed. Microstructure and mechanical properties of these membranes were also determined. Zn-doped membranes have inhibited in vivo and in vitro bacterial colonization. Zn-alloy and Zn-doped membranes attained good biocompatibility and were found to be non-toxic to cells. The Zn-doped matrices showed feasible mechanical properties, such as flexibility, strength, complex modulus and tan delta. Zn incorporation in polymeric membranes provided the highest regenerative efficiency for bone healing in experimental animals, potentiating osteogenesis, angiogenesis, biological activity and a balanced remodeling. Zn-loaded membranes doped with SiO2 nanoparticles have performed as bioactive modulators provoking an M2 macrophage increase and are a potential biomaterial for promoting bone repair. Zn-doped membranes have promoted pro-healing phenotypes.

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Real-Time Expanded Field-of-View for Minimally Invasive Surgery Using Multi-Camera Visual Simultaneous Localization and Mapping

Sensors ◽

10.3390/s21062106 ◽

2021 ◽

Vol 21 (6) ◽

pp. 2106

Author(s):

Ahmed Afifi ◽

Chisato Takada ◽

Yuichiro Yoshimura ◽

Toshiya Nakaguchi

Keyword(s):

Minimally Invasive Surgery ◽

Minimally Invasive ◽

Real Time ◽

Invasive Surgery ◽

Simultaneous Localization And Mapping ◽

Field Of View ◽

Time Dynamic ◽

Matrix Estimation ◽

Localization And Mapping

Minimally invasive surgery is widely used because of its tremendous benefits to the patient. However, there are some challenges that surgeons face in this type of surgery, the most important of which is the narrow field of view. Therefore, we propose an approach to expand the field of view for minimally invasive surgery to enhance surgeons’ experience. It combines multiple views in real-time to produce a dynamic expanded view. The proposed approach extends the monocular Oriented features from an accelerated segment test and Rotated Binary robust independent elementary features—Simultaneous Localization And Mapping (ORB-SLAM) to work with a multi-camera setup. The ORB-SLAM’s three parallel threads, namely tracking, mapping and loop closing, are performed for each camera and new threads are added to calculate the relative cameras’ pose and to construct the expanded view. A new algorithm for estimating the optimal inter-camera correspondence matrix from a set of corresponding 3D map points is presented. This optimal transformation is then used to produce the final view. The proposed approach was evaluated using both human models and in vivo data. The evaluation results of the proposed correspondence matrix estimation algorithm prove its ability to reduce the error and to produce an accurate transformation. The results also show that when other approaches fail, the proposed approach can produce an expanded view. In this work, a real-time dynamic field-of-view expansion approach that can work in all situations regardless of images’ overlap is proposed. It outperforms the previous approaches and can also work at 21 fps.

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An injectable and self-healing hydrogel with covalent cross-linking in vivo for cranial bone repair

Journal of Materials Chemistry B ◽

10.1039/c7tb00776k ◽

2017 ◽

Vol 5 (20) ◽

pp. 3739-3748 ◽

Cited By ~ 22

Author(s):

Shaoyu Lü ◽

Xiao Bai ◽

Haidi Liu ◽

Piao Ning ◽

Zengqiang Wang ◽

...

Keyword(s):

Click Chemistry ◽

Bone Repair ◽

Cranial Bone ◽

Cross Linking ◽

Self Healing

DA click chemistry and dynamic acylhydrazone bond cross-linking are employed to obtain injectable and self-healing hydrogels for cranial bone repair.

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Role of Herbal Agents - Tea Tree Oil and Aloe vera as Cavity Disinfectant Adjuncts in Minimally Invasive Dentistry- An In vivo Comparative Study

JOURNAL FOR CLINICAL AND DIAGNOSTIC RESEARCH ◽

10.7860/jcdr/2017/27598.10147 ◽

2017 ◽

Author(s):

Gaurav Patri

Keyword(s):

Minimally Invasive ◽

Comparative Study ◽

Aloe Vera ◽

Tea Tree Oil ◽

Tea Tree ◽

Minimally Invasive Dentistry

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The relationship between lymphangion chain length and maximum pressure generation established through in vivo imaging and computational modeling

AJP Heart and Circulatory Physiology ◽

10.1152/ajpheart.00003.2017 ◽

2017 ◽

Vol 313 (6) ◽

pp. H1249-H1260 ◽

Cited By ~ 9

Author(s):

Mohammad S. Razavi ◽

Tyler S. Nelson ◽

Zhanna Nepiyushchikh ◽

Rudolph L. Gleason ◽

J. Brandon Dixon

Keyword(s):

Nitric Oxide ◽

Smooth Muscle ◽

Minimally Invasive ◽

Chain Length ◽

Maximum Pressure ◽

Computational Simulations ◽

A Chain ◽

Lymphatic Pumping ◽

The Relationship

The intrinsic contraction of collecting lymphatic vessels serves as a pumping system to propel lymph against hydrostatic pressure gradients as it returns interstitial fluid to the venous circulation. In the present study, we proposed and validated that the maximum opposing outflow pressure along a chain of lymphangions at which flow can be achieved increases with the length of chain. Using minimally invasive near-infrared imaging to measure the effective pumping pressure at various locations in the rat tail, we demonstrated increases in pumping pressure along the length of the tail. Computational simulations based on a microstructurally motivated model of a chain of lymphangions informed from biaxial testing of isolated vessels was used to provide insights into the pumping mechanisms responsible for the pressure increases observed in vivo. These models suggest that the number of lymphangions in the chain and smooth muscle cell force generation play a significant role in determining the maximum outflow pressure, whereas the frequency of contraction has no effect. In vivo administration of nitric oxide attenuated lymphatic contraction, subsequently lowering the effective pumping pressure. Computational simulations suggest that the reduction in contractile strength of smooth muscle cells in the presence of nitric oxide can account for the reductions in outflow pressure observed along the lymphangion chain in vivo. Thus, combining modeling with multiple measurements of lymphatic pumping pressure provides a method for approximating intrinsic lymphatic muscle activity noninvasively in vivo while also providing insights into factors that determine the extent that a lymphangion chain can transport fluid against an adverse pressure gradient. NEW & NOTEWORTHY Here, we report the first minimally invasive in vivo measurements of the relationship between lymphangion chain length and lymphatic pumping pressure. We also provide the first in vivo validation of lumped parameter models of lymphangion chains previously developed through data obtained from isolated vessel testing.

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