Surface treatment methods for cementless implantable medical devices

A method of producing a bioactive surface on a medical device configured for cementless implantation, the medical device comprising a porous commercially pure titanium metal or titanium alloy coating on PEEK or PEKK polymer, the method comprising the following sequential steps:

• treating the medical device with an acidic solution consisting of nitric acid at a concentration in the range of 3 M to 10 M, and hydrofluoric acid at a concentration in the range of 0.1 M to 1 M, at a temperature between 20° C. and 60° C., to form an activated surface on the medical device, wherein an extent of etching relative to a total surface area is 15% or less;
• treating the activated surface using a plasma electrolytic oxidation process in an electrolyte solution comprising calcium and phosphate salts, at a temperature between 15° C. and 50° C., to form an oxidized surface on the medical device comprising a microporous oxide layer having bioactive elements, compounds, or phases, the microporous oxide layer at least comprising hydroxyapatite, and wherein an extent of uniformity of the microporous oxide layer relative to total surface area treated is at least 85%;
• and
• chemically treating the resulting oxidized surface of the medical device with an alkaline solution comprising a hydroxide at a concentration in the range of 0.01 M to 5.0 M, at a temperature between 20° C. and 90° C., to form a bioactive surface on the medical device, the bioactive surface comprising a structure selected from the group consisting of:
• a nanofibrous network, a composite of a nanofibrous network and calcium phosphate particles, and a composite of the nanofibrous network, calcium phosphate particles and a film comprising hydroxyapatite, wherein the particles or film are formed on the surface of the nanofibrous network;
• wherein the bioactive surface further comprises calcium and phosphorus in a calcium to phosphorous atomic percentage ratio of about 1.67 and sodium in atomic percentage range of 0.5 to 10.

A method of producing an antibacterial and bioactive surface on a medical device configured for cementless implantation, the method comprising the following sequential steps:

• providing a medical device comprising a surface and formed of commercially pure titanium metal or a titanium alloy, wherein the surface is dense;
• treating the medical device with an acidic solution consisting of nitric acid at a concentration in the range of 5 M to 10 M, hydrofluoric acid at a concentration in the range of 0.1 M to 2 M, at a temperature between 40° C. and 60° C., to form an activated surface on the medical device, wherein an extent of etching relative to a total surface area is 15% or less;
• washing the activated surface on the medical device in water for 5-30 minutes at a temperature in the range of 40° C. to 60° C., to remove residual acidic solution from the surface;
• treating the washed activated surface using a plasma electrolytic oxidation process in an electrolyte solution comprising calcium and phosphate salts, at a temperature between 15° C. and 50° C., to form an oxidized surface on the medical device comprising a microporous oxide layer having bioactive elements, compounds, or phases, the microporous oxide layer at least comprising hydroxyapatite, and wherein an extent of uniformity of the microporous oxide layer relative to total surface area treated is at least 85%;
• washing the oxidized medical device in water for 5 to 60 minutes, to remove salts from the electrolyte solution that are physically adsorbed onto the medical device;
• and
• chemically treating the resulting oxidized surface of the medical device with an alkaline solution comprising a hydroxide at a concentration in the range of 0.01 M to 5.0 M, at a temperature between 20° C. and 90° C., to form a bioactive surface on the medical device, the bioactive surface comprising a structure selected from the group consisting of:
• a nanofibrous network, a composite of a nanofibrous network and calcium phosphate particles, and a composite of the nanofibrous network, calcium phosphate particles and a film comprising hydroxyapatite, wherein the particles or film are formed on the surface of the nanofibrous network;
• washing the resulting medical device in water to remove physically adsorbed ions from the surface of the medical device;
• treating the resulting medical device with an iodine-containing solution to obtain the antibacterial and bioactive surface, wherein iodine is incorporated into the microporous oxide layer or bioactive surface by (i) electrodeposition, or (ii) submersion in the iodine-containing solution at a temperature between 25° C. to 60° C.;
• washing the resulting medical device with water to remove residual iodine from the surface of the medical device;
• and
• drying the medical device.

A method of producing a bioactive surface on a medical device configured for cementless implantation, the medical device comprising a surface and comprised of a sintered bead porous coating made of commercially pure titanium metal or a titanium alloy, the method comprising the following sequential steps:

• treating the medical device with an acidic solution consisting of nitric acid at a concentration in the range of 3 M to 10 M, hydrofluoric acid at a concentration in the range of 0.1 M to 1 M, at a temperature between 20° C. and 60° C., to form an activated surface on the medical device, wherein an extent of etching relative to a total surface area is 15% or less;
• treating the activated surface using a plasma electrolytic oxidation process in an electrolyte solution comprising calcium and phosphate salts, at a temperature between 15° C. and 50° C., to form an oxidized surface on the medical device comprising a microporous oxide layer having bioactive elements, compounds, or phases, the microporous oxide layer at least comprising hydroxyapatite, and wherein an extent of uniformity of the microporous oxide layer relative to total surface area treated is at least 85%;
• and
• chemically treating the resulting oxidized surface of the medical device with an alkaline solution comprising a hydroxide at a concentration in the range of 0.01 M to 5.0 M, at a temperature between 20° C. and 90° C., to form a bioactive surface on the medical device, the bioactive surface comprising a structure selected from the group consisting of:
• a nanofibrous network, a composite of a nanofibrous network and calcium phosphate particles, and a composite of the nanofibrous network, calcium phosphate particles and a film comprising hydroxyapatite, wherein the particles or film are formed on the surface of the nanofibrous network;
• wherein the bioactive surface further comprises calcium and phosphorus in a calcium to phosphorous atomic percentage ratio from 1.50 to 1.74.