**10. Self-endothelializing titanized blood contacting surface for Biomechanical Hearts**

Titanium has proven itself as the leading structured metallic biomaterial for 50 years [13]. One reason for this widespread use is the excellent biocompatibility of the metal and its alloys [14]. Theoretically, surface coating of the blood contacting PTFE may open new avenues for improving biocompatibility of this kind of implant material. However, a titanium coating on PTFE seemed not to be possible until now due to the high temperatures needed for commonly used sputtering techniques. Therefore a novel coating method was used [15] for PTFE applying a plasma activated chemical gas deposition (PACVD) at temperatures of 30-35°C. **Plasma- Titanium Treatment for Collagen Coating at 35 Co**

**Removal of free aldehyde**

**Figure 23.** Principle of titanium coating at low temperature (see text).

PACVD is a coating technology (Pfm Titanium GmbH, Nürnberg, Germany, patent number EP 0 897 997 A1) where the so called precursor (Tetrakisdimethylamidotitanium, Ti [N(CH3)2]4) is transferred into the gas phase and brought into the reactor by a carrier gas like nitrogen gas [16]. The plasma is able to supply the substrate with high energy while the temperature during deposition can be kept low at about 30-35°C. Within that non-thermal plasma with high electron temperatures but neutrons and ions at room temperature, solely the electrons can follow a quickly changing electrical field with a typical frequency of 13.56 MHz under low pressure plasma as described in detail elsewhere [17]. The precursor, or part of it, reacts with the substrate and creates a layer of 30nm in thickness (Figure 23).

The blood contacting surface of the PTFE-made pumping chamber was titanized as described above. This titan surface attracts progenitor cells derived from the bone marrow which were delivered into circulation. The seeded cells transform into endothelial cells within time [18]. This kind of self-tissue engineering of the blood contacting surface is mandatory to prevent thrombo-embolism mainly for blood pumps contracting on demand [14].

**10. Self-endothelializing titanized blood contacting surface for**

a plasma activated chemical gas deposition (PACVD) at temperatures of 30-35°C.

**Figure 23.** Principle of titanium coating at low temperature (see text).

**Plasma- Titanium Treatment for Collagen Coating at 35 Co**

Titanium has proven itself as the leading structured metallic biomaterial for 50 years [13]. One reason for this widespread use is the excellent biocompatibility of the metal and its alloys [14]. Theoretically, surface coating of the blood contacting PTFE may open new avenues for improving biocompatibility of this kind of implant material. However, a titanium coating on PTFE seemed not to be possible until now due to the high temperatures needed for commonly used sputtering techniques. Therefore a novel coating method was used [15] for PTFE applying

PACVD is a coating technology (Pfm Titanium GmbH, Nürnberg, Germany, patent number EP 0 897 997 A1) where the so called precursor (Tetrakisdimethylamidotitanium, Ti [N(CH3)2]4) is transferred into the gas phase and brought into the reactor by a carrier gas like nitrogen gas [16]. The plasma is able to supply the substrate with high energy while the temperature during deposition can be kept low at about 30-35°C. Within that non-thermal plasma with high electron temperatures but neutrons and ions at room temperature, solely the electrons can follow a quickly changing electrical field with a typical frequency of 13.56 MHz under low pressure plasma as described in detail elsewhere [17]. The precursor, or part

of it, reacts with the substrate and creates a layer of 30nm in thickness (Figure 23).

**Removal of free aldehyde Groups by plasma ernergy**

**Biomechanical Hearts**

360 Regenerative Medicine and Tissue Engineering

**Figure 24.** Thrombosis of the total blood contacting surface 8 weeks after implantation (left): Isolated thrombus for‐ mation from the PTFE- pumping chamber (right).

**Figure 25.** Titanized PTFE pumping chamber 6.5 months after implantation without any thrombus formation. This thin cover could be identified as an endothelial layer by a von Willebrand immun-histological staining.

**Figure 26.** Clinical setting of a BMH in an aorto-aortic configuration
