scholarly journals Nanoarchitectonics on living cells

RSC Advances ◽  
2021 ◽  
Vol 11 (31) ◽  
pp. 18898-18914
Author(s):  
Katsuhiko Ariga ◽  
Rawil Fakhrullin

We can introduce functional structures with various components on a living cell as if architectures were constructed on material surfaces.

2010 ◽  
Vol 5 (1) ◽  
pp. 90-96
Author(s):  
Aleksandr V. Kopylov ◽  
Viktor Ya. Prinz

The possibility of application of the novel class of tubular needles for piercing cells and injecting biological material inside the cell is considered. Stability calculations of tubular (multiwall) needles were made. Calculations were made for the needles with walls formed from hybrid graphene-semiconductor or graphene structures and spires shaped as trapeziform open cylindrical shells. The possibility of mass fabrication of such needles and chips for AFM significantly broadens the range of available operations on the surface and inside the living cell and opens prospects of effective high-precision manipulations with individual cells.


Author(s):  
Daniel M. Dubois ◽  
Stig C. Holmberg

A survey of the Varela automata of autopoiesis is presented. The computation of the Varela program, with initial conditions given by a living cell, is not able to self-maintain the membrane of the living cell. In this chapter, the concept of anticipatory artificial autopoiesis (AAA) is introduced. In this chapter, the authors present a new algorithm of the anticipatory artificial autopoiesis, which extend the Varela automata. The main enhancement consists in defining an asymmetric membrane of the artificial lining cell. The simulations show the anticipatory generation of artificial living cells starting with any initial conditions. The new concept of anticipatory artificial autopoiesis is related to artificial life (Alife) and artificial intelligence (AI). This is a breakthrough in the computational foundation of autopoiesis.


Nanoscale ◽  
2020 ◽  
Vol 12 (16) ◽  
pp. 9133-9143 ◽  
Author(s):  
Pablo D. Garcia ◽  
Carlos R. Guerrero ◽  
Ricardo Garcia

Method to measure the viscoelastic properties of a living cell by AFM-based force–distance curves.


Recent work on the osmotic pressure of the hen’s egg has introduced a sense of uncertainty as to the value of the many comparisons which have been made between osmotic pressures of the blood, body fluids, and surrounding media. The uncertainty pertains not to theory but to a simple matter of fact and, as this involves that most fundamental datum for biological theory—viz., the state of the water in the living cell—there is urgent need to have it cleared up. The fact in dispute is the freezing point of the yolk and white of the bird’s egg. Atkins in 1909 by measurements, obviously made with the greatest care, found “no difference between the freezing point of white and yolk of the same egg and a mixture of white and yolk gave the same depression.” Atkins (1909) used the ordinary Beckmann technique and so, too, did Straub (1929) twenty years later, but with a surprisingly different result for he found a constant difference between white and yolk of the hen’s egg amounting on the average to —0·15° C. A. V. Hill (1930) confirmed Straub’s (1929) finding by a different method. He compared the fall in temperature caused by evaporation with that of water and from the difference calculated the osmotic pressure. Howard (1932) using the Beckmann method again found no difference in the freezing point of white and yolk. In these measurements the yolk was puddled by stirring so that at sometime or another the structure was broken down. Yolk is not only a chemical complex but it is alive, gross mechanical disturbance might, therefore, have the effect it usually has on living cells and cause chemical breakdown with consequent fall of the freezing point. Hale’s experiments were designed to explore this possibility by observing directly the freezing point of intact yolk and white.


1997 ◽  
Vol 3 (S2) ◽  
pp. 133-134 ◽  
Author(s):  
Ammasi Periasamy ◽  
Richard N. Day

The pituitary specific transcription factor Pit-1 is required for transcriptional activity of the prolactin (PRL) gene. The Pit-1 protein is a member of the POU homeodomain transcription factors that is expressed in several different anterior pituitary cell types, where it functions as an important determinant of pituitary-specific gene expression. The Pit-1 protein generally interacts with DNA elements in the PRL gene promoter as a dimer, and has been demonstrated to associate with other transcription factors. The objective of our research is to define the critical molecular events involved in transcriptional regulation of the PRL gene in living cells. Methods that allow monitoring of the intimate interactions between protein partners in living cells provide an unparalleled perspective on these biological processes. Using the jellyfish green fluorescent protein (GFP) as a tag, we applied the fluorescence resonance energy transfer (FRET) technique to visualize where and when the Pit-1 protein interacts in the living cell. FRET is a quantum mechanical effect that occurs between donor (D) and acceptor (A) fluorophores provided: (i) the emission energy of D is coincident with the energy required to excite A, and (ii) the distance that separating the two fluorophores is 10-100 Å. Mutant forms of GFP that fluoresce either green or blue (BFP) have excitation and emission spectra that are suitable for FRET imaging.


Micromachines ◽  
2020 ◽  
Vol 11 (5) ◽  
pp. 495
Author(s):  
Takayuki Shibata ◽  
Hiromi Furukawa ◽  
Yasuharu Ito ◽  
Masahiro Nagahama ◽  
Terutake Hayashi ◽  
...  

Atomic force microscopy (AFM) is an effective platform for in vitro manipulation and analysis of living cells in medical and biological sciences. To introduce additional new features and functionalities into a conventional AFM system, we investigated the photocatalytic nanofabrication and intracellular Raman imaging of living cells by employing functionalized AFM probes. Herein, we investigated the effect of indentation speed on the cell membrane perforation of living HeLa cells based on highly localized photochemical oxidation with a catalytic titanium dioxide (TiO2)-functionalized AFM probe. On the basis of force–distance curves obtained during the indentation process, the probability of cell membrane perforation, penetration force, and cell viability was determined quantitatively. Moreover, we explored the possibility of intracellular tip-enhanced Raman spectroscopy (TERS) imaging of molecular dynamics in living cells via an AFM probe functionalized with silver nanoparticles in a homemade Raman system integrated with an inverted microscope. We successfully demonstrated that the intracellular TERS imaging has the potential to visualize distinctly different features in Raman spectra between the nucleus and the cytoplasm of a single living cell and to analyze the dynamic behavior of biomolecules inside a living cell.


1920 ◽  
Vol 32 (5) ◽  
pp. 583-593 ◽  
Author(s):  
O. T. Avery ◽  
Glenn E. Cullen

1. A method is described for the preparation of an active enzyme-containing solution of pneumococci, in which no living cells are present. These enzymes are capable of hydrolyzing sucrose, starch, and inulin. 2. The invertase and amylase of pneumococcus are active within the limits pH 5 to 8, with an optimum reaction of about pH 7. This reaction range corresponds closely with limiting hydrogen ion concentrations which define growth of the organism in the presence of carbohydrate. 3. These studies indicate that the enzymes described are not true secretory products of the living cell, but are of the nature of endoenzymes, since their activity can be demonstrated only when cell disintegration has occurred.


1946 ◽  
Vol 29 (3) ◽  
pp. 181-192 ◽  
Author(s):  
W. J. V. Osterhout

The chloroplast of Spirogyra is a long, spirally coiled ribbon which may contract to form a short, nearly straight rod. This happens under natural conditions and it can also be produced by a variety of inorganic salts and by some organic substances. It also occurs when the chloroplast is freed by centrifugal force from the clear peripheral protoplasm which is in contact with the cellulose wall. It would therefore seem that the chloroplast may be passively stretched by the action of the clear protoplasm and hence it contracts as soon as it is set free. This contraction happens in dead as well as in living cells. It would be of much interest to know how the protoplasm brings about the coiling of the chloroplast and how the chloroplast is set free by various reagents. Presumably they must penetrate the living protoplasm to produce the effects described. In one species partial contraction without detachment from the peripheral protoplasm can be brought about by lead acetate. This is reversible. Lead nitrate does not produce this result. The attack upon the problem is greatly facilitated by the study of dead cells. Thereby we reduce the number of variables but the chloroplast continues to react to certain chemical and physical agents in much the same manner as in the living cell and the solution surrounding it can be controlled as is not possible in the living cell. We must await further investigation to learn what plant and animal cells contain gels under tension and what functions they perform.


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