scholarly journals Microneedle Arrays for Sampling and Sensing Dermal Interstitial Fluid

2021 ◽  
Author(s):  
Navid Kashaninejad ◽  
Ahmed Munaz ◽  
Hajar Moghadas ◽  
Sharda Yadav ◽  
Muhammad Umer ◽  
...  
Keyword(s):  
Interstitial Fluid ◽  
Point Of Care ◽  
Disease Diagnosis ◽  
Future Directions ◽  
Microneedle Arrays ◽  
In Situ Detection

Dermal interstitial fluid (ISF) is a novel source of biomarkers that can be considered as an alternative to blood sampling for disease diagnosis and treatment. Nevertheless, in vivo extraction and analysis of ISF are challenging. On the other hand, microneedle (MN) technology can address most of the challenges associated with dermal ISF extraction and is well-suited for long-term, continuous ISF monitoring as well as in situ detection. In this review, we first briefly summarise the different dermal ISF collection methods and compare them with MN methods. Next, we elaborate on the design considerations and biocompatibility of MNs. Subsequently, the fabrication technologies of various MNs used for dermal ISF extraction, including solid MNs, hollow MNs, porous MNs and hydrogel MNs, are thoroughly explained. In addition, different sensing mechanisms of ISF detection will be discussed in detail. Subsequently, we identify the challenges and propose the possible solutions associated with ISF extraction. A detailed investigation is provided for the transport and sampling mechanism of ISF in vivo. Also, the current in vitro skin model integrated with the MN arrays will be discussed. Finally, future directions to develop a point-of-care (POC) device to sample ISF are proposed.

scholarly journals Microneedle Arrays for Sampling and Sensing Skin Interstitial Fluid

Chemosensors ◽  
2021 ◽  
Vol 9 (4) ◽  
pp. 83
Author(s):  
Navid Kashaninejad ◽  
Ahmed Munaz ◽  
Hajar Moghadas ◽  
Sharda Yadav ◽  
Muhammad Umer ◽  
...  
Keyword(s):  
Interstitial Fluid ◽  
Point Of Care ◽  
Disease Diagnosis ◽  
Sensing Skin ◽  
Microneedle Arrays ◽  
In Situ Detection

Dermal interstitial fluid (ISF) is a novel source of biomarkers that can be considered as an alternative to blood sampling for disease diagnosis and treatment. Nevertheless, in vivo extraction and analysis of ISF are challenging. On the other hand, microneedle (MN) technology can address most of the challenges associated with dermal ISF extraction and is well suited for long-term, continuous ISF monitoring as well as in situ detection. In this review, we first briefly summarise the different dermal ISF collection methods and compare them with MN methods. Next, we elaborate on the design considerations and biocompatibility of MNs. Subsequently, the fabrication technologies of various MNs used for dermal ISF extraction, including solid MNs, hollow MNs, porous MNs, and hydrogel MNs, are thoroughly explained. In addition, different sensing mechanisms of ISF detection are discussed in detail. Subsequently, we identify the challenges and propose the possible solutions associated with ISF extraction. A detailed investigation is provided for the transport and sampling mechanism of ISF in vivo. Also, the current in vitro skin model integrated with the MN arrays is discussed. Finally, future directions to develop a point-of-care (POC) device to sample ISF are proposed.

The Primary Investigation on Biological Effect of Mesoporous Bioactive Glass In Vivo

2013 ◽  
Vol 750-752 ◽  
pp. 1651-1655
Author(s):  
Bai Yan Sui ◽  
Cheng Tie Wu ◽  
Jiao Sun
Keyword(s):  
Bioactive Glass ◽  
Biological Effect ◽  
Degradation Products ◽  
Long Term Effect ◽  
Liver And Kidney ◽  
Mesoporous Bioactive Glass

Mesoporous bioactive glass (MBG) has superior bioactivity and degradation than non-mesoporous bioactive glass (BG) in vitro. But the biological effect of MBG in vivo is still unknown. In this study, MBG powders with 20μm were implanted into the femoral condyles in SD rats. BG powders with 20μm were used as a control. The local degradation and osteogenesis were observed at 1 week and 4 weeks after implantation, and the systemic toxicity of the degradation products were also evaluated simultaneously. The results revealed MBG powders had the faster rate of degradation and better osteogenesis effect than BG powders at 4 weeks, although the most of material still remained in situ. Histopathological analyses indicated the degradation products did not have any damage to major organs such as liver and kidney. In conclusion, this preliminary study demonstrated that MBG powders have more excellent biological effect at 4 weeks than that of BG in vivo. However the long-term effect needs to be confirmed.

scholarly journals Conjugate formation in urea: coupling of insoluble peptides to alkaline phosphatase for ELISA and in situ detection of antibody-forming cells.

1991 ◽  
Vol 39 (7) ◽  
pp. 987-992 ◽  
Author(s):  
K Gerritse ◽  
M Fasbender ◽  
W Boersma ◽  
E Claassen
Keyword(s):  
Alkaline Phosphatase ◽  
Synthetic Peptide ◽  
Enzyme Linked Immunosorbent Assay ◽  
Sufficient Degree ◽  
Antipeptide Antibody ◽  
In Situ Detection ◽  
Antibody Secreting Cells

We report here a new method to produce synthetic peptide/alkaline phosphatase (AP) conjugates in the presence of urea. The method allows the use of peptides that are not soluble to a sufficient degree in aqueous buffers. The presence of 8 M urea during the construction of the synthetic peptide/AP conjugates does not influence enzyme activity nor the affinity of the anti-peptide antibodies for the conjugated peptide. We demonstrate that these synthetic peptide/AP conjugates can be used for detection of specific antipeptide antibody-forming cells (AFC) in vivo. This method for constructing enzyme conjugates with insoluble proteins or peptides suggest not only new possibilities for detection of specific AFC in vivo but also for applications in receptor-ligand studies, ELISA (enzyme-linked immunosorbent assay), and spot ELISA for detection of antibody-secreting cells in vitro.

scholarly journals Long-term evolution of antibiotic persistence in P. aeruginosa lung infections

2021 ◽  
Author(s):  
Melanie Ghoul ◽  
Sandra B Andersen ◽  
Helle Krogh Johansen ◽  
Lars Jelsbak ◽  
Søren Molin ◽  
...  
Keyword(s):  
Pathogenic Bacteria ◽  
Resistance Mechanisms ◽  
Term Evolution ◽  
Bacterial Clone ◽  
Evolution Of Resistance ◽  
Lung Infections

Pathogenic bacteria respond to antibiotic pressure with the evolution of resistance but survival can also depend on their ability to tolerate antibiotic treatment, known as persistence. While a variety of resistance mechanisms and underlying genetics are well characterised in vitro and in vivo, the evolution of persistence, and how it interacts with resistance in situ is less well understood. We assayed for persistence and resistance with three clinically relevant antibiotics: meropenem, ciprofloxacin and tobramycin, in isolates of Pseudomonas aeruginosa from chronic cystic fibrosis lung infections spanning up to forty years of evolution. We find evidence that persistence is under positive selection in the lung and that it can particularly act as an evolutionary stepping stone to resistance. However, this pattern is not universal and depends on the bacterial clone type and antibiotic used, indicating an important role for antibiotic mode of action.

scholarly journals Acellular Small-Diameter Tissue-Engineered Vascular Grafts

2019 ◽  
Vol 9 (14) ◽  
pp. 2864 ◽  
Author(s):  
Zhen Li ◽  
Xinda Li ◽  
Tao Xu ◽  
Lei Zhang
Keyword(s):  
Effective Means ◽  
Vascular Grafts ◽  
Small Diameter ◽  
Test Results ◽  
In Vivo Test ◽  
Current State

Tissue-engineered vascular grafts (TEVGs) are considered one of the most effective means of fabricating vascular grafts. However, for small-diameter TEVGs, there are ongoing issues regarding long-term patency and limitations related to long-term in vitro culture and immune reactions. The use of acellular TEVG is a more convincing method, which can achieve in situ blood vessel regeneration and better meet clinical needs. This review focuses on the current state of acellular TEVGs based on scaffolds and gives a summary of the methodologies and in vitro/in vivo test results related to acellular TEVGs obtained in recent years. Various strategies for improving the properties of acellular TEVGs are also discussed.

A muscle-powered energy delivery system and means for chronic in vivo testing

1999 ◽  
Vol 86 (6) ◽  
pp. 2106-2114 ◽  
Author(s):  
Dennis R. Trumble ◽  
James A. Magovern
Keyword(s):  
In Vitro Tests ◽  
Access Port ◽  
Wide Range ◽  
Piston Displacement ◽  
In Vivo Testing ◽  
Implant Testing

Electrically stimulated skeletal muscle represents a potentially unlimited source of energy for the actuation of motor prostheses. Devices to harvest and deliver contractile power have proven mechanically feasible, but long-term efficacy has not been demonstrated. This report describes recent refinements in muscle energy converter (MEC) design and details the development of an implantable afterload chamber (IAC) designed to facilitate implant testing. The IAC comprises a fluid-filled bladder housed within a titanium cylinder that connects directly to the MEC. A vascular access port allows percutaneous measurement and adjustment of air pressure within the housing and provides a means both to monitor MEC function and to control hydraulic loading conditions. Data from in vitro tests show that IAC pressure mirrors changes in MEC-piston displacement over a wide range of actuation speeds and stroke lengths. Stroke lengths and actuation forces calculated from IAC pressure readings were typically found to be within 5% of measured values. This testing scheme may yield important information in regard to the ability to harness energy from in situ muscle over prolonged periods.

scholarly journals In situ type I oligomeric collagen macroencapsulation promotes islet longevity and function in vitro and in vivo

2018 ◽  
Vol 315 (4) ◽  
pp. E650-E661 ◽  
Author(s):  
Clarissa Hernandez Stephens ◽  
Kara S. Orr ◽  
Anthony J. Acton ◽  
Sarah A. Tersey ◽  
Raghavendra G. Mirmira ◽  
...  
Keyword(s):  
Islet Transplantation ◽  
Cellular Therapy ◽  
Foreign Body Response ◽  
Type I ◽  
Pancreatic Islet Transplantation ◽  
And Function

Widespread use of pancreatic islet transplantation for treatment of type 1 diabetes (T1D) is currently limited by requirements for long-term immunosuppression, limited donor supply, and poor long-term engraftment and function. Upon isolation from their native microenvironment, islets undergo rapid apoptosis, which is further exacerbated by poor oxygen and nutrient supply following infusion into the portal vein. Identifying alternative strategies to restore critical microenvironmental cues, while maximizing islet health and function, is needed to advance this cellular therapy. We hypothesized that biophysical properties provided through type I oligomeric collagen macroencapsulation are important considerations when designing strategies to improve islet survival, phenotype, and function. Mouse islets were encapsulated at various Oligomer concentrations (0.5 –3.0 mg/ml) or suspended in media and cultured for 14 days, after which viability, protein expression, and function were assessed. Oligomer-encapsulated islets showed a density-dependent improvement in in vitro viability, cytoarchitecture, and insulin secretion, with 3 mg/ml yielding values comparable to freshly isolated islets. For transplantation into streptozotocin-induced diabetic mice, 500 islets were mixed in Oligomer and injected subcutaneously, where rapid in situ macroencapsulation occurred, or injected with saline. Mice treated with Oligomer-encapsulated islets exhibited rapid (within 24 h) diabetes reversal and maintenance of normoglycemia for 14 (immunocompromised), 90 (syngeneic), and 40 days (allogeneic). Histological analysis showed Oligomer-islet engraftment with maintenance of islet cytoarchitecture, revascularization, and no foreign body response. Oligomer-islet macroencapsulation may provide a useful strategy for prolonging the health and function of cultured islets and has potential as a subcutaneous injectable islet transplantation strategy for treatment of T1D.

In vitro and in vivo polysaccharides assembly: ultrastructural and cytochemical study of growing plant cell wall components.

1978 ◽  
Vol 36 (2) ◽  
pp. 434-435
Author(s):  
D. Reis ◽  
B. Vian ◽  
J. C. Roland
Keyword(s):  
Cell Wall ◽  
Self Assembly ◽  
Plant Cell Wall ◽  
Higher Plants ◽  
Three Dimensional ◽  
Cytochemical Study ◽  
Wall Components

Wall morphogenesis in higher plants is a problem still open to controversy. Until now the possibility of a transmembrane control and the involvement of microtubules were mostly envisaged. Self-assembly processes have been observed in the case of walls of Chlamydomonas and bacteria. Spontaneous gelling interactions between xanthan and galactomannan from Ceratonia have been analyzed very recently. The present work provides indications that some processes of spontaneous aggregation could occur in higher plants during the formation and expansion of cell wall.Observations were performed on hypocotyl of mung bean (Phaseolus aureus) for which growth characteristics and wall composition have been previously defined.In situ, the walls of actively growing cells (primary walls) show an ordered three-dimensional organization (fig. 1). The wall is typically polylamellate with multifibrillar layers alternately transverse and longitudinal. Between these layers intermediate strata exist in which the orientation of microfibrils progressively rotates. Thus a progressive change in the morphogenetic activity occurs.

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