*5.1.3. Skin electroporation*

Molecule or DNA vaccine can transport across targeted tissue of human skin is of great interest for transdermal drug delivery and non-invasive chemical sensing. Skin has capability to produce therapeutic molecules, which not only acts as a systematically or locally, but it can create immunological response, when antigen presenting cells will be targeted. The skin containing antigen presenting cells like dendritic cells, langerhans cells, and mononuclear cells. The gene delivery through the skin electroporation is feasible, efficient and comparable to other tissues [171]. The first skin electroporation study was observed in Newborn mice which transfected with a plasmid coding for a neomycin resistance gene [172]. The transfection efficiency can depend upon the age of the skin, where the higher transfection efficiency can be achieve for younger mice compare to the older mice [173]. Skin electroporation, only clinical study has been reported belonging to metastatic melanoma [118]. To date, the skin electropo‐ ration has been studied broadly for animal infectious diseases. For most cases Hapatitis B has been investigated for animals through skin electroporation [137,174-176]. Also experiments have been performed vaccine against HIV, smallpox, malaria [177-179].

### **5.2. Single cell electroporation**

By using single cell electroporation technique, it is possible to deliver the molecules such as drugs, DNA, RNA, peptide, nucleic acid into the cell membrane in vivo and vitro for single cell analysis. The plasmid delivery inside the cell membrane with high efficiency in adherent cells and tissues has been studied in vitro [180-184] and in vivo [52,183-186]. Fig.7. show the different applications of single cell electroporation, where membrane can permeabilized to transport protein, small and large molecules inside the single cell.

When two single cells are closed to each other, then cell fusion can occur. Due to high electric field strength, which exceeds the critical value of cell membrane, irreversible electroporation can occur, resulting in cell membrane rapture and finally cell death. This electroporation

300-5000 fold [159-161]. Different types of cancer can be treated by electroporation techni‐ que. The prostate cancer is one of the most common cancer, which is increasing day to day. For this cancer prostate specific antigen (PSA), targeted to the prostate cancer cell for immunotherapeutic approach. The phase I clinical trials with PSA DNA vaccine for human prostate cancer is safe and which can include cellular and humoral immune responses against PSA protein [162-163]. The PSA-DNA vaccine has been investigated by electroporation technique [164-165]. Electroporation treated with CD4+, CD8+ cells and antibodies were detected in patient successfully with safe and tolerated mode. Electrochemotherapy has also been investigated for treatment of human colorectal cell line and liver tumours [166-167]. The local treatment of electrochemotherapy (ECT) with master cell tumours of Dog has been experimented in where size of the tumors was 5.2 cm3 and 2.9 cm3 treated by surgery and ECT. The ECT treatment was easy, effective and safe local treatment for master cell tumors of Dogs [168]. Recently, electrochemotherapy has been developed in more advancement for treat ment of internal tumors using surgical procedures, endoscopic routes or percutane‐

Molecule or DNA vaccine can transport across targeted tissue of human skin is of great interest for transdermal drug delivery and non-invasive chemical sensing. Skin has capability to produce therapeutic molecules, which not only acts as a systematically or locally, but it can create immunological response, when antigen presenting cells will be targeted. The skin containing antigen presenting cells like dendritic cells, langerhans cells, and mononuclear cells. The gene delivery through the skin electroporation is feasible, efficient and comparable to other tissues [171]. The first skin electroporation study was observed in Newborn mice which transfected with a plasmid coding for a neomycin resistance gene [172]. The transfection efficiency can depend upon the age of the skin, where the higher transfection efficiency can be achieve for younger mice compare to the older mice [173]. Skin electroporation, only clinical study has been reported belonging to metastatic melanoma [118]. To date, the skin electropo‐ ration has been studied broadly for animal infectious diseases. For most cases Hapatitis B has been investigated for animals through skin electroporation [137,174-176]. Also experiments

By using single cell electroporation technique, it is possible to deliver the molecules such as drugs, DNA, RNA, peptide, nucleic acid into the cell membrane in vivo and vitro for single cell analysis. The plasmid delivery inside the cell membrane with high efficiency in adherent cells and tissues has been studied in vitro [180-184] and in vivo [52,183-186]. Fig.7. show the different applications of single cell electroporation, where membrane can permeabilized to

When two single cells are closed to each other, then cell fusion can occur. Due to high electric field strength, which exceeds the critical value of cell membrane, irreversible electroporation can occur, resulting in cell membrane rapture and finally cell death. This electroporation

ous approaches to gain access to the treatment area [169-170].

82 Advances in Micro/Nano Electromechanical Systems and Fabrication Technologies

have been performed vaccine against HIV, smallpox, malaria [177-179].

transport protein, small and large molecules inside the single cell.

*5.1.3. Skin electroporation*

**5.2. Single cell electroporation**

**Figure 7.** Different application of single cell electroporation. When external applied electric field reaches to the threshold values of the cell membrane, then cell membrane can permeabilized to deliver protein, small and large mol‐ ecules inside the cell. If two single cells are close to each other, then cell fusion can occur. To apply an intense electric field, which exceeds certain critical value, irreversible electroporation can occur resulting cell membrane rapture and finally cell death. Figure has redrawn from reference. Figure has redrawn with reprint permission obtained from Springer [187].

successfully investigated cell to cell intracellular biochemical variation from millions of cells. However this technique needs a lot of research in the future for more improvement because this technology is in underdeveloped stage. For intracellular targeting, single cell electropo‐ ration based systems can be developed for genomic characterization, where a tagged antisense oligonucleotide is introduced to block expression and proteins can be profile by tagged markers [188]. To reduce the electrode size in nanoscale label, selective manipulation of single organelles within a cell can be possible. Thus the localized single cell membrane electropora‐ tion (LSCMEP) concept has come in frontier research in last several years [61-63]. This technique can control spatial-temporal process successfully and its have ability to monitor the transfection results in real time situation. To reduce the electrode size in nanoscale label, effective electroporation region should be reduce. As results transfection efficiency should be increase with high cell viability. Florescent markers with single cell electroporation permits direct visualization of cell morphology, cell growth, and intracellular events over timescales ranging from seconds to days. Fluorescent dye or plasmid DNA can enter the neurons with the intact brain of albino Xenopus tadpoles [189]. Individual neurons can be elctroporated by this technique in vivo and in vitro including mature and fully differentiated neurons. The transfection of neurons into brain slices and in intact brains of living animals is possible to use this technique. The neuron transfection achievable up to 1 mm dip into a tissue and electro‐ physiological recording of individual neuron was possible by use of SCEP [190]
